Abstract:Recently, drug resistance due to the extensive abuse and over-use of antibiotics has become an increasingly serious problem, making the development of alternative antibiotics a very urgent issue. In this study, the Chinese herbal medicine, Polygonum cuspidatum, was extracted with 95% ethanol and the crude extracts were further purified by partition based on solvent polarity. The antimicrobial activities of the extracts and fractions were determined by the disk diffusion and minimum inhibitory concentration (MIC) methods. The results showed that the ethyl ether fraction (EE) of the ethanol extracts possesses a broader antimicrobial spectrum and greater antimicrobial activity against all of the tested clinical drug-resistant isolates, with a range of MIC values between 0.1-3.5 mg/mL. The active extract showed complete inhibition of pathogen growth and did not induce resistance to the active components. In addition, according to scanning electron microscope observations, EE resulted in greater cell morphological changes by degrading and disrupting the cell wall and cytoplasmic membrane, whereby ultimately this cell membrane integrity damage led to cell death. In conclusion, the EE extracts from Polygonum cuspidatum may provide a promising antimicrobial agent for therapeutic applications against nosocomial drug-resistant bacteria.
Abstract:Monitoring of winding faults is the most important item used to determine the maintenance status of a transformer. Commonly used methods for winding-fault diagnosis require the transformer to exit operation before testing and an external exciting signal, whether the transformer is malfunctioning or not. However, if an overvoltage signal can be regarded as a broadband excitation source for fault diagnosis, then the interference caused by signal injection can be eliminated without the need for additional pulse or impulse signals. In this paper, a tapped transformer is designed and test platforms are built to compare winding diagnoses using the impulse wave and sweep frequency response analysis methods by recording voltage responses on both the high-and low-voltage sides and calculating the respective transfer functions. Based on comparison of statistical indicators, it is found that the sensitivities of both methods are similar for detecting conditions of winding-ground and winding-interlayer short circuits. It is concluded that it is feasible to use a transient overvoltage monitoring system for winding-fault diagnosis.
In the recent years, chronic obstructive pulmonary disease (COPD) has been found to be associated with a higher risk of new-onset osteoporotic fracture (NOF). However, the existence of such an association in the COPD patients receiving statin treatment remains unknown. The present study aimed to investigate the association between COPD and NOF in statin-treated patients.
The present study was conducted over a period of 10 years (January 2004 to December 2013) in Taiwan. COPD patients receiving statin treatment were included in the statin user group, whereas the randomly selected statin non-users, with 1:1 matching for sex, age, index date, and Charlson Comorbidity Index, were included in the statin non-user group. The hazard ratio (HR) of NOFs in COPD patients was estimated between statin user and non-user groups.
A total of 86,188 cases were identified as the statin-treated patients, and 86,188 subjects were included in the control group of statin non-users. Initially, the risk of NOF was found to be higher among the statin users as compared to non-users [HR, 1.12; 95% confidence interval (CI), 1.01–1.25]. However, the calculation of risk for NOFs after the adjustment for age, sex, comorbidities, and concurrent medications indicated no association of NOF (HR, 0.81; 95% CI, 0.55–1.21) with COPD in patients receiving statin treatment as compared to statin non-users.
The results of the study provided first evidence for the absence of any association between COPD and NOFs in statin-treated patients during a follow-up period of 10 years. Thus, the findings of this study might support the hypothesis stating the potent pleiotropic effects of statins. In clinical practice, these drugs might prove beneficial for the patients with COPD.
In this paper, the ternary soft set is discussed based on the soft triadic (complete) formal context. The ternary soft set is a generalization of Molodsov’s soft set, which can characterize the objects universe more clearly by the attributes set, and different from type-2 soft set. The definitions of the ternary soft set and ternary formal context are given and illustrated with some examples. A mindmap is used to show the idea of ternary soft set visually. The usage of bijective soft set enables fast decision making process by our work. We demonstrate the idea with a flowchart and a case study. Meanwhile, the soft operations among the ternary soft sets are defined and their properties are studied.
Winding status is an important part of transformer fault diagnosis. In this paper, the diagnosis test platform includes a reduced-scale transformer with the connection group model of Ynyn0, and its voltage ratio is 10 kV/0.4 kV. The voltage response of single-phase windings of three-winding transformers with varying degrees of short-circuit faults is measured under a damped oscillation wave with an amplitude of 4 kV and an equivalent frequency of 20 kHz. The transfer function of high-voltage phase and its corresponding low-voltage phase in the normal and fault condition is calculated. Three characteristic criterion of the transfer function are analysed in order to diagnose short-circuit faults in single-phase windings of three-winding transformers.
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