The Application of Wireless Underground Sensor Networks to Monitor Seepage inside an Earth Dam.

Earth dams or embankments are susceptible to instability due to internal seepage, piping, and erosion, which can lead to catastrophic failure. Therefore, monitoring the seepage water level before the dam collapses is an important task for early warning of dam failure. Currently, there are hardly any monitoring methods that use wireless underground transmission to monitor the water content inside earth dams. Real-time monitoring of changes in the soil moisture content can more directly determine the water level of seepage. Wireless transmission of sensors buried underground requires signal transmission through the soil medium, which is more complex than traditional air transmission. Henceforth, this study establishes a wireless underground transmission sensor that overcomes the distance limitation of underground transmission through a hop network. A series of feasibility tests were conducted on the wireless underground transmission sensor, including peer-to-peer transmission tests, multi-hop underground transmission tests, power management tests, and soil moisture measurement tests. Finally, field seepage tests were conducted to apply wireless underground transmission sensors to monitor the internal seepage water level before an earth dam failure. The findings show that wireless underground transmission sensors can achieve the monitoring of seepage water levels inside earth dams. In addition, the results supersede those of a conventional water level gauge. This could be crucial in early warning systems during the era of climate change, which has caused unprecedented flooding events.

Thermal monitoring and analysis of the large-scale field earth-dam breach process.

Thermal imaging is a nondestructive testing method for monitoring internal material changes that are indicated by changes in an object's surface temperature. In this study, field observation using thermographs was applied to monitor and analyze the breach process of large-scale earth dams. The earth dam test site was Landao Creek in Nantou County, Taiwan. Four field tests were performed to monitor and analyze a single earth dam and two successive earth dams. Ponding first occurred at the lowland of the riverbed upstream, and base seepage occurred at the base of the dam downstream; overtopping failure soon followed. Earth-dam failure mode is affected by the topographic characteristics of the riverbed; specifically, lowland areas are prone to ponding upstream, which causes piping and seepage downstream as well as subsequent breaches. Ponding and piping cause water seepage and soil wetting, which are reflected in lower surface temperatures recorded on thermographs. Thermographs can monitor changes in surface temperature to evaluate the potential failure modes of dams. Dam surfaces with large temperature variations may be potential failure areas. If confirmed, this fact may prove useful for failure-mode prediction. This paper proposes a monitoring index to reflect the temperature changes in a given period, and this study verified it empirically.

A high-throughput method based on microwave-assisted extraction and liquid chromatography-tandem mass spectrometry for simultaneous analysis of amphetamines, ketamine, opiates, and their metabolites in hair.

A total sample-preparation and analysis time of 50 min is required for the high-throughput method of hair analysis proposed in this paper. The method is applicable to analysis of drugs commonly used in Asia, and their metabolites--methamphetamine (MA), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), ketamine (K), norketamine (NK), dehydronorketamine (DHNK), 6-acetylmorphine (6-AM), morphine (MOR), and codeine (COD). Cut and weighed hair (10 mg) was incubated for 3 min with methanol-trifluoroacetic acid (TFA) during microwave-assisted extraction (MAE) at 700 W. The incubation solution was evaporated, the residue was reconstituted in deionized water-methanol, 99:1 (v/v), and 20 µL was injected on to a core-shell column (50 × 4.6 mm, 2.6 µm particle size) for liquid chromatographic-tandem mass spectrometric (LC-MS-MS) analysis. Gradient elution separation was performed in 8 min at a flow rate of 1 mL min(-1). No signal interfering with any of the analytes was found in fourteen blank hair samples from different sources. The limits of detection and quantification were 0.5 pg mg(-1) and 2.0 pg mg(-1), respectively, for MA, AMP, MDMA, MDA, K, NK, and DHNK, and 2.0 pg mg(-1) and 5.0 pg mg(-1), respectively, for 6-AM, MOR and COD. The linear range was between the LOQ and 1000 pg mg(-1), and the correlation coefficients were all greater than 0.999. Investigation of matrix effects revealed that all the analytes were suppressed by less than 20% and the standard deviation (SD) was always less than 7%. Recovery was always greater than 90% and the SD for each compound was less than 6%. Precision and accuracy for each analyte were within 15%. Eight authentic hair specimens from known drug abusers were successfully analyzed. Compared with traditional overnight incubation methods, the rapid 3-min extraction time achieved similar or greater extraction yields. Sample preparation by MAE was a reliable procedure for extraction of the analytes from hair but substantially simpler and faster than other methods.

Molecular diagnosis of periprosthetic joint infection by quantitative RT-PCR of bacterial 16S ribosomal RNA.

The diagnosis of periprosthetic joint infection is sometimes straightforward with purulent discharge from the fistula tract communicating to the joint prosthesis. However it is often difficult to differentiate septic from aseptic loosening of prosthesis because of the high culture-negative rates in conventional microbiologic culture. This study used quantitative reverse transcription polymerase chain reaction (RT-qPCR) to amplify bacterial 16S ribosomal RNA in vitro and in 11 clinical samples. The in vitro analysis demonstrated that the RT-qPCR method was highly sensitive with the detection limit of bacterial 16S rRNA being 0.148 pg/ µ l. Clinical specimens were analyzed using the same protocol. The RT-qPCR was positive for bacterial detection in 8 culture-positive cases (including aerobic, anaerobic, and mycobacteria) and 2 culture-negative cases. It was negative in one case that the final diagnosis was confirmed without infection. The molecular diagnosis of bacterial infection using RT-qPCR to detect bacterial 16S rRNA around a prosthesis correlated well with the clinical findings. Based on the promising clinical results, we were attempting to differentiate bacterial species or drug-resistant strains by using species-specific primers and to detect the persistence of bacteria during the interim period before the second stage reimplantation in a larger scale of clinical subjects.

Integration of GC/EI-MS and GC/NCI-MS for simultaneous quantitative determination of opiates, amphetamines, MDMA, ketamine, and metabolites in human hair.

In this paper, the possibility of using a multiple ionization mode approach of GC/MS was developed for the simultaneous hair testing of common drugs of abuse in Asia, including amphetamines (amphetamine, AP; methamphetamine, MA; methylenedioxy amphetamine, MDA; methylenedioxy methamphetamine, MDMA; methylenedioxy ethylamphetamine, MDEA), ketamine (ketamine, K; norketamine, NK), and opiates (morphine, MOR; codeine, COD; 6-acetylmorphine, 6-AM). This strategy integrated the characteristics of gas chromatography-mass spectrometry (GC-MS) using electron impact ionization (EI) and negative chemical ionization (NCI). Hair samples (25 mg) were washed, cut, and incubated overnight at 25 degrees C in methanol-trifluoroacetic acid (methanol-TFA). The samples were extracted by solid phase extraction (SPE) procedure, derivatized using heptafluorobutyric acid anhydride (HFBA) at 70 degrees C for 30 min, and the derivatives analyzed by GC-MS with EI and NCI. The limit of detection (LOD) with GC/EI-MS analysis obtained were 0.03 ng/mg for AP, MA, MDA, MDMA, and MDEA; 0.05 ng/mg for K, NK, MOR, and COD; and 0.08 ng/mg for 6-AM. The LOD of GC/NCI-MS analysis was much lower than GC/EI-MS analysis. The LOD obtained were 30 pg/mg for AP and MDA in GC/EI-MS and 2 pg/mg in GC/NCI-MS. Therefore, the sensitivity of AP and MDA in GC/NCI-MS was improved from 15-fold compared with EI. The sensitivity of AP, MA, MDA, MDMA, MDEA, MOR, and COD was improved from 15- to 60-fold compared with EI. In addition, the sensitivity of 6-AM increased 8-fold through selection of m/z 197 for the quantitative ion. Moreover, K and NK could dramatically improve their sensitivity at 200- and 2000-fold. The integration of GC/EI-MS and GC/NCI-MS can obtain the high sensitivity and complementary results of drugs of abuse in hair. Six hair samples from known drug abusers were examined by this new strategy. These results show that integrating the characteristics of GC/EI-MS and GC/NCI-MS were not only enhancement of the sensitivity but also avoid wrong results and wrong interpretations of correct results.

Quarantine Vapor Heat Treatment of Papaya Fruit for Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae).

The presence of quarantine insect pests in fruit export can impede trade with other countries. Therefore, to reduce the risk of possible quarantine pests in exported fruit, postharvest disinfestation treatment is essential. This study investigated the effects of vapor heat treatment (VHT) on oriental fruit fly (Bactrocera dorsalis Hendel (Diptera: Tephritidae)) and melon fly (Bactrocera cucurbitae Coquillett (Diptera: Tephritidae)) which are major pests for papaya fruits. For inoculated papaya fruits weighing 550 ± 100 g, the optimal egg-inoculation density, rearing conditions, and heat tolerance for each developmental stages of both fruit flies were determined, and then analyzed to determine their survival, and assess papaya fruit quality after treatment. Result of VHT of each developmental stage indicated that the eggs of B. dorsalis were the most heat tolerant at 45.6°C. Efficacy test that determined the optimal mortality temperature was performed by subjecting 60 fruits infested with 4,500 eggs to fruit core temperatures of 44.2, 45.2, 46.2, and 47.2°C. It was found that when the papaya fruit core temperature increased at a heating rate of 0.0925°C/min from room temperature to 47.2°C in 3 h, fruit flies showed 100% mortality. Results of the confirmatory test using 300 papaya fruits also indicated 100% mortality at this temperature. Both fruit quality and injury test results demonstrated insignificant differences in color, appearance, soluble solids, or firmness of fruits before and after treatment. Thus, VHT effectively disinfested papaya fruits against both fruit fly species, thus making it a viable quarantine treatment for papaya fruits prior to their export.

Seismology-based early identification of dam-formation landquake events.

Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1-3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.

Perinatal effects of combined use of heroin, methadone, and amphetamine during pregnancy and quantitative measurement of metabolites in hair.

OBJECTIVE: There has been very limited research on the clinical features of newborns exposed to combined use of heroin, methadone, and amphetamine in the uterus. We describe a technique for the quantification of drug metabolites in neonatal hair samples. METHODS: In a tertiary neonatal care center in Taiwan, three neonates whose mothers self-reported heroin abuse with methadone treatment during pregnancy were studied. Involuntary exposure to amphetamine was not suspected before the births. To assess long-term illicit drug exposure during pregnancy, a quantifying technique of gas chromatography/mass spectrometry (GC/MS) for hair samples from neonates was developed to replace current methods for urine and blood specimens. RESULTS: All three mothers were addicted to heroin and prescribed oral methadone treatment during pregnancy. Two males and one female were born and then admitted to the neonatal intensive care unit because of apparent neonatal abstinence syndrome (NAS) after birth. Additional hypertonicity and cerebral dysfunction were also diagnosed by electroencephalography in one case. Supportive care was given to the neonates, unless special treatments were needed in responding to tachypnea, fetal distress, or withdrawal symptoms. During follow-up periods from 10 months to 15 months, the signs of NAS remained and delays in milestones of development were observed. Further follow-up on the infants' neurobehavioral development is necessary. Measurement results of neonates' hair samples revealed high levels of metabolites of heroin, methadone, and amphetamine, reflecting the amount of illicit drug exposure 2-3 months before delivery. CONCLUSION: The current study suggested the possibility of polydrug exposure, which was previously unknown in pregnant women in Taiwan. Measurement of neonatal hair samples could provide a basis for clinical evaluation and potential corresponding treatment.

Evaluation of differentially expressed genes by shear stress in human osteoarthritic chondrocytes in vitro.

BACKGROUND: The pathogenesis of osteoarthritis is related to abnormal mechanical stresses that alter cartilage metabolism and chondrocyte survival. Among the mechanical stresses, shear stress is held responsible for the development of arthritis. METHODS: Monolayer cultures of human osteoarthritic chondrocytes were subjected to fluid-induced shear stress in vitro. A cDNA microarray technology was used to screen the differentially regulated genes and quantitative real-time poly-merase chain reaction (Q-RT-PCR) was used to confirm the results. The significance of the expression ratio for each gene was determined on the lowest associated false discovery rate calculated from the changes of gene expression in relation to the standard deviation of repeated measurements for that gene. RESULTS: Exposure of human osteoarthritic chondrocytes to shear stress (0.82 Pa) for 2 hours differentially regulated 373 and 227 clones in two independent microarray analyses with at least a 1.7-fold change. By comparing the differentially regulated clones, 14 upregulated and 6 downregulated genes were identified. Many of the differentially expressed genes were related to cell proliferation/differentiation (TGF-beta, acidic FGF), cell survival/apoptosis (CYP1B1, BCL2L3, TNFRSF11B, chemokine ligands, ADM), and matrix homeostasis (DCN, SDC2, MGP, WISP2). CONCLUSION: The gene expression patterns following shear stress show a high similarity to the gene expression in the reparative process of osteoarthritis chondrocytes. Using microarray analysis, this study suggests a close interaction between shear stress and the pathogenesis of osteoarthritis.

Simultaneous quantitative determination of amphetamines, ketamine, opiates and metabolites in human hair by gas chromatography/mass spectrometry.

A gas chromatography/mass spectrometry (GC/MS) method was developed and validated for the determination of common drugs of abuse in Asia. The method was able to simultaneously quantify amphetamines (amphetamine; AP, methamphetamine; MA, methylenedioxy amphetamine; MDA, methylenedioxymeth mphetamine; MDMA, methylenedioxy ethylamphetamine; MDEA), ketamine (ketamine; K, norketamine; NK), and opiates (morphine; MOR, codeine; COD, 6-acetylmorphine; 6-AM) in human hair. Hair samples (25 mg) were washed, cut, and incubated overnight at 25 degrees C in methanol/trifluoroacetic acid (methanol/TFA). The samples were extracted by solid-phase extraction (SPE), derivatized using heptafluorobutyric acid anhydride (HFBA) at 70 degrees C for 30 min, and the derivatives were analyzed by electron ionization (EI) GC/MS in selected ion monitoring mode. Confirmation was accomplished by comparing retention times and the relative abundances of selected ions with those of standards. Deuterated analogs of the analytes were used as internal standards for quantification. Calibration curves for ten analytes were established in the concentration range 0.1-10 ng/mg with high correlation coefficients (r2 > 0.999). The intra-day and inter-day precisions were within 12.1% and 15.8%, respectively. The intra-day and inter-day accuracies were between -8.7% and 10.7%, and between -5.9% and 13.8%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 0.03 and 0.05 ng/mg for AP, MA, MDA, MDMA and MDEA; 0.05 and 0.08 ng/mg for K, NK, MOR and COD; and 0.08 and 0.1 ng/mg for 6-AM. The recoveries were above 88.6% for all the compounds, except K and NK which were in the range of 71.7-72.7%. Eight hair samples from known polydrug abusers were examined by this method. These results show that the method is suitable for broad-spectrum drug testing in a single hair specimen.

Inhibition of severe acute respiratory syndrome coronavirus replication by niclosamide.

Antiviral agents are urgently needed to fight severe acute respiratory syndrome (SARS). We showed that niclosamide, an existing antihelminthic drug, was able to inhibit replication of a newly discovered coronavirus, SARS-CoV; viral antigen synthesis was totally abolished at a niclosamide concentration of 1.56 microM, as revealed by immunoblot analysis. Thus, niclosamide represents a promising drug candidate for the effective treatment of SARS-CoV infection.