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Dexmedetomidine (DMED), an alpha-2 adrenoreceptor agonist, has been widely used in regional anesthesia procedures. However, the effect of DMED on local anesthetic cardiotoxicity has not been well delineated. This study consisted of two experiments. In experiment A, 42 Sprague–Dawley (SD) rats were randomly divided into 6 groups (n = 7), each group was pretreated with DMED 0 μg kg−1 (D0 group), 1 μg kg−1 (D1 group), 3 μg kg−1 (D3 group), 6 μg kg−1 (D6 group), 12 μg kg−1 (D12 group), and 24 μg kg−1 (D24 group), administered through the right femoral vein. In experiment B, 20 SD rats were randomly divided into 4 groups (n = 5), such as control group, DMED group, yohimbine (YOH) group, and DMED + YOH group. Each subgroup in experiment B was also pretreated similarly as in experiment A. After pretreatment of rats as described above (in experiments A and B), bupivacaine 2.5 mg kg−1 min−1 was infused to induce cardiac arrest. In experiment A, the lethal dose threshold of bupivacaine and plasma bupivacaine concentration in D3 and D6 group were higher than the other groups. In experiment B, there was no interaction between DMED and YOH in lethal dose threshold, arrhythmia time, plasma concentration of bupivacaine, and myocardial content of bupivacaine. DMED doses of 3–6 μg kg−1 elevated the lethal dose threshold of bupivacaine without involvement of the alpha-2 adrenoceptors. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer is a malignant tumor with high incidence rate and mortality rate. Purpose: In this study, we investigated the anti-cancer effect of alantolactone, a sesquiterpene lactone, on gastric cancer cell lines BGC-823 and SGC-7901. Methods: BGC-823 and SGC-7901 cells were treated with different concentrations of alantolactone, Hoechst 33258 staining, flow cytometry, wound healing assay, invasion assay, colony forming assay, quantative polymerase chain reaction, and western blot analysis were used to evaluate the anticancer activity of alantolactone to gastric cancer. Results: Alantolactone induced apoptosis of gastric cancer cells by regulating the expression of Bax, Bcl-2, and p53, which related to intrinsic apoptotic pathway, and suppressed colony formation, migration, and invasion by mediating the expression of matrix metalloproteinase (MMP)-2, MMP-7, and MMP-9. Cell signaling pathway analysis showed that alantolactone enhanced the phosphorylation of p38 and decreased the translocation of nucleus p65, suggesting that the apoptosis-promoting and migration-suppressing effect of alantolactone might at least partially rely on regulating p38 mitogen-activated protein kinase (p38MAPK) pathway and nuclear factor-κB (NF-κB) pathway. Conclusions: Alantolactone can be used as a potential therapeutic agent for treating gastric cancer. [ABSTRACT FROM AUTHOR]

This paper presents the experimental modal analysis of the Canton Tower from the ambient vibration measurements under different earthquake excitation conditions. Firstly, the time history and Power Spectral Density (PSD) of the acceleration response under different earthquake excitations have been compared. Secondly, two output-only modal identification techniques are applied to the field measurements under earthquake excitations to identify the dynamic properties of the tower, namely, the Frequency Domain Decomposition (FDD) and the Subspace Stochastic Identification (SSI). At last, the Hilbert-Huang transform (HHT) method is applied to obtain the instantaneous frequencies and energy distribution under different loadings in the time-frequency domain and the results are compared with those from wavelet transform. The modal properties of the Canton Tower presented in this paper can be used as baseline for structural health monitoring and the analysis of dynamic characteristic of the high-rise structures under different earthquake excitations in future. [ABSTRACT FROM AUTHOR]

Modal parameters and modal flexibility obtained from the modal experiment have been used for damage identification in frequency domain. These two methods are compared in this paper numerically and experimentally. The optimization objective function of the former method is a weighted function of the frequency and mode shape residues, in which different weights can be assigned to the frequencies and mode shapes so that their degrees of accuracy can be taken into account. The optimization objective function of the latter method is the modal flexibility residue. Based on the same modal data, the two methods are compared from different aspects, including the damage configurations and uncertainties in the modal data. Results show that using the modal parameters directly can detect damage more accurately and reliably than using the modal flexibility. [ABSTRACT FROM AUTHOR]

Shear connectors are widely used in composite bridges that provide composite action. Their damage will reduce the load-carrying capacity of the structure. In this study, a novel method based on Kullback-Leibler distance (KLD) was developed to assess the integrity of the shear connectors. A bridge model was constructed in the laboratory and some removable anchors were specially designed and fabricated to link the beams and slab that were cast separately. Each anchor consists of a threaded bar that penetrates through the soffit of the beam and ties up into an embedded nut cap to simulate a shear connector in the real bridges. Different damage scenarios were introduced by pulling out some connectors. Vibration tests were carried out in each damage scenario. Various damage detection methods have been applied and results show that the method was able to detect all the assumed damage scenarios successfully and consistently. [ABSTRACT FROM AUTHOR]

Objective: To study the effect of different oxygen therapies on the rats with carbon dioxide poisoning for screening out the best on-the-spot oxygen-therapy technology for treating acute carbon dioxide poisoning. Methods: The 60 healthy male Sprague Dawley rats were randomly divided into normal control group (A group), carbon dioxide poisoning group (B group), low-concentration oxygen inhalation treatment group (C group), high-concentration oxygen inhalation treatment group (D group) and hyperbaric oxygen-therapy group (E group). Various kinds of oxygen therapies were given after the contamination. The pH, partial pressure of oxygen (PO2) and partial pressure of carbon dioxide (PCO2) of arterial blood, serum troponin I (CTNI), creatine kinase (CK), glutamic-oxaloacetic transaminase (AST), γ-glutamyl transpeptidase (GGT), blood urea nitrogen (BUN), potassium (K), sodium (Na) and chlorine (Cl) for the rats of each group were inspected. The lung and the brain tissues were taken for observing the pathological changes.Results: There is no significant difference in pH, PO2 and PCO2 among all oxygen-therapy groups (p > 0.05). The levels of CTNI, CK and AST in E group are obviously lower than that in B, C and D groups (p < 0.05). The level of serum K in E group is obviously lower than that in B, C and D groups (p < 0.05). The levels of serum Na and Cl in E group are obviously higher than that in B, C and D groups (p < 0.05). The pathological change of lungs in E group is significantly better than that in C and D groups. Conclusions: We recommend that the medical units with related conditions can give the hyperbaric oxygen therapy to patients as soon as possible [ABSTRACT FROM AUTHOR]

Massive infrastructure projects developed in Hong Kong make for big challenges and unique opportunities for engineers and researchers. The construction of the cables-stayed Stonecutters Bridge sets up a new landmark in the bridge engineering community, with its main span exceeding 1,000 m as well as its sophisticated instrumentation system comprising more than 1,500 sensors. The development of structural health monitoring (SHM) technology has evolved for over 10 years in Hong Kong since the implementation of the so-called 'Wind And Structural Health Monitoring System (WASHMS)' on the suspension Tsing Ma Bridge in 1997. The successful engineering paradigms of implementing and operating SHM systems for five cable-supported bridges and experiences gained by practice and research in the past decade have promoted the applications of this technology beyond Hong Kong and extending from long-span bridges to high-rise structures. In this paper, the evolution in the design methodology for SHM systems, the advancement in several aspects of SHM technology, and a performance comparison between the early implemented and lately developed SHM systems for large-scale bridges are first outlined. Subsequently, the concept of the so-called 'life-cycle structural health monitoring (LSHM)' is addressed by exploring the integration of in-construction monitoring and in-service monitoring and by realizing such an integrated system to a super-tall tower structure. The issue on how an SHM system benefits structural vibration control is also discussed. [ABSTRACT FROM AUTHOR]

The tribological performance of PA6 and carbon fiber reinforced polyamide 6 (CF/PA6) under dry sliding condition was examined. Different contents of carbon fibers were employed as reinforcement. All filled and unfilled polyamide 6 composites were tested against CGr15 ball and representative testing was performed. The effects of carbon fiber content on tribological properties of the composites were investigated. The worn surface morphologies of neat PA6 and its composites were examined by scanning electron microscopy and the wear mechanisms were discussed. Moreover, all filled polyamide 6 have superior tribological characteristics to unfilled polyamides 6. The optimum wear reduction was obtained when the content of carbon fiber is 20 vol%. [ABSTRACT FROM AUTHOR]

A comparison was made of the effects of coupling reagent surface modification and air oxidation on the improvement of the interfacial adhesion of carbon fibres in reinforced polyamide composites. Results showed that coupling reagent modification greatly strengthens the adhesion between the reinforcement and matrix and is superior to improvements produced by surface oxidation in air. The optimum interfacial adhesion was reached at 0·3 wt-% coupling reagent concentration. The thermal expansion behaviour of the carbon fibre reinforced polyamide composite also showed that coupling reagent modification improved the interfacial adhesion. [ABSTRACT FROM AUTHOR]

Although vibration-based structural damage detection methods have demonstrated various degrees of success, the damage detection of civil structures still remains as a challenging task. The main obstacles include the insensitivity to local damage and the high sensitivity to measurement noise. A new structural damage detection method based on the statistical moments of dynamic responses of a structure has been recently proposed by the authors, and the numerical study manifested that the proposed method is sensitive to local structural damage but insensitive to measurement noise. The experimental investigation on this method is presented in this article. Three shear building models with and without damage were built and subjected to ground motions generated by a shaking table. The displacement and acceleration responses of each building model at each floor were recorded. The recorded ground motion and building responses as well as identified structural damping ratios were then used to identify damage locations and severities using the statistical moment-based damage detection method. The identified damage locations and severities were compared with the theoretical values. The comparison is found satisfactory, and the method proposed is effective and feasible. [ABSTRACT FROM AUTHOR]

Exposure to arsenic in drinking water is known to produce a variety of health problems, including peripheral neuropathy. Auditory, visual and somatosensory impairment have been reported in Mongolian farmers living in the Yellow River Valley, where drinking water is contaminated by arsenic. In the present study, sensory tests, including pinprick and vibration thresholds, were administered to 320 residents with well-water arsenic levels, ranging from non-detectable to 690 μg/L. Vibration thresholds in the second and fifth fingers of both hands were measured using a vibrothesiometer. Drinking water, urine and toenail samples were obtained to assess arsenic exposure and body burden. Regression analyses indicated significant associations of pinprick scores and vibration thresholds with all arsenic measures. Vibration thresholds were more strongly associated with urinary than water or nail arsenic measures, but odds ratios for decreased pinprick sensitivity were highest for the water arsenic measure. Results of the current study indicate neurosensory effects of arsenic exposure at concentrations well below the 1000 μg/L drinking water level specified by NRC, and suggest that non-carcinogenic end-points, such as vibration thresholds, are useful in the risk assessment of exposure to arsenic in drinking water. [ABSTRACT FROM AUTHOR]

Using both qualitative (in-depth, personal interviews) and quantitative (self-report survey indices) techniques, data were collected from 43 women involved in streetwalking prostitution. The purpose of the investigation was to examine exposure to violence and victimization among a particularly vulnerable female population across the life span. A secondary goal was to apply stress theory as an organizing framework for examining personal resources (e.g., social support, locus of control) and coping behavior. Results from both data collection strategies are presented, and implications for intervention are described. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editors discuss various reports within the issue on topics including energy dissipation and vibration isolation of mechanical systems and structures, structural damage detection, as well as general behavior of laminated structures and plate.