2,984 research outputs found
Determination of Outflow Properties for the Quasi-thermal Radiation-Dominated Gamma-Ray Bursts
Some gamma-ray bursts (GRBs) are observed with prompt phase changing from
quasi-thermal to non-thermal emission. The quasi-thermal emission is always
well described by a multi-color blackbody function, and based on this modeling,
a characteristic temperature with corresponding flux is taken as a probe to
diagnose the magnetization properties of the central engine with the `top-down'
approach proposed by Gao \& Zhang. Furthermore, the initial radius of the
acceleration for the outflow as well as the magnetization parameter
() could be constrained to within a narrower range than those with a
pair of temperature and flux from modeling with a single blackbody plus an
empirical function (BAND function or exponential cut-off power law). We apply
this method to some bursts with known emission properties, such as GRB 210121A
from a typical pure hot fireball and GRB 210610B from a hybrid jet. It is found
that this method works well on these control samples. With this method, we find
it is suggestive that the photospheric emission of GRB 221022B is mainly from a
fireball, rather than from a hybrid jet, while the non-thermal component is
caused by internal shock (IS) mechanism, due to the increasing Lorentz Factor
with time.Comment: 9 pages, 3 figures, submitted to ApJ on 06-May-202
Kinetics of Steam Gasification of Brown Coal and Volatile-Char Interactions
Victorian brown coal has high reactivity for gasification because of catalysis of inherent AAEM species. It was, however, found recently that the inhibitory effects of the volatile-char interactions on char gasification are not negligible. In this study, the effects of volatiles were examined with a novel fluidised-bed/fixed-bed reactor, and the mechanisms and kinetics model of the char gasification and volatile-char interactions were discussed to describe quantitatively the inhibition of volatiles about char gasification. Victorian brown coal sample was gasified with steam at 800 °C at various feeding rates. As a result, char yields became higher at higher feeding rate at the same feeding time because of the volatile-char interactions. The elementary reactions of the char gasification and volatile-char interactions were proposed and the L-H type reaction rate equations for brown coal gasification were newly derived, and the kinetics model was verified by the comparison with experiments. The experimental data of the char yields and the concentrations of Na in gasified char were able to be estimated by theproposed kinetics model. This model would be useful to estimate the performance of the gasifier for Victorian brown coal
Comparison of Sterile and Clean Dressing Techniques in Post-operative Surgical Wound Infection in a Chinese Healthcare Facility
Purpose: To investigate the effect of sterile and clean dressing techniques on wound management in a Chinese hospital, and to compare their impact on wound healing and the cost of the dressing materials with respect to postoperative surgical wounds.Methods: A total of 130 patients, comprising 70 (53.8 %) males and 60 (46.2 %) females, who had undergone surgery in The Affiliated Hospital of Changchun Traditional Chinese Medicine University, Changchun, China in 2012 – 2014 were enrolled in the study. Of these, 65 (50 %) received sterile dressings and 65 (50 %) clean dressings. A control group comprising 25 patients, 15 (60 %) males and 10 (40 %) females, who attended the clinic for change dressings only, was also included. The patients’ dressings were changed four times daily with 2x sterile and 2x clean dressings. Details of all the changes, including the nutritional status of the patients, were recorded. The patients were followed-up up to the time of their discharge.Results: Twelve (18.5 %) patients out of those who received sterile or clean dressings were found to have acquired an infection. The size of the wounds was approximately 1.8 to 32.4 cm3 (mean: 5.2 ± 6.4 cm3) in size at the start of the study and 0.6 to 4.2 cm3 at the end of the study. A significant difference was identified between the sterile and clean dressing groups at the beginning of the study (U = 72.5; p < 0.12). A decrease in wound size was observed in both of these groups but was not statistically significant, while the change in wound volume, was significantly different (U = 84.5; p < 0.25). When the cost of the two dressing types was compared, the sterile items were more expensive than that of the clean items; thus, sterile dressing procedure was significantly more costly than clean dressing procedure (p < 0.01).Conclusion: With mounting concern regarding antimicrobial resistance and hospital-acquired infections, suitable wound dressing techniques are required to prevent infection and reduce the duration of wound healing after surgery without compromising patient safety.Keywords: Wound dressing, Postoperative, Antimicrobial resistance, Hospital acquired infection
Clinical efficacy and safety of edaravone therapy in acute cerebral haemorrhage
Purpose: To evaluate the clinical efficacy and safety of edaravone in the treatment of acute cerebral haemorrhage (ACH).Methods: This study recruited 120 patients who developed ACH. The patients were divided into control and treatment groups with 60 patients per group. The control group underwent conventional treatment and the treatment group also received intravenous edaravone. The volumes of cerebral edema and cerebral hematoma, high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) levels, and Chinese Stroke Scale (CSS) score before and after treatment were compared between the two groups.Results: The respective cerebral edema volumes of the control and treatment groups decreased from 20.99 ± 12.09 and 21.80 ± 12.01 mL on day 0 to 11.23 ± 6.34 and 12.11 ± 5.98 mL at day 7 and 4.69 ± 4.03 and 4.64 ± 3.9 mL on day 14 (P < 0.05). The respective cerebral hematoma volumes of the control and treatment groups decreased from 18.98 ± 12.04 and 18.97 ± 12.07 mL on day 0 to 12.34 ± 6.57 and 11.89 ± 4.01 mL at day 7 and 9.49 ± 3.95 and 9.52 ± 3.96 mL on day 14. Compared with pretreatment, hs-CRP and IL-6 levels and CSS score of the two groups decreased significantly following treatment (p < 0.05); the differences in the cerebral edema and hematoma volumes of the two groups on days 7 and 14 were not significant (p > 0.05). The hs-CRP and IL-6 levels and CSS scores of the treatment group decreased appreciably (p < 0.05), while the incidence of adverse reactions in the treatment and control groups was 16.67 and 13.33 %, respectively, but the difference was not significant (p > 0.05).Conclusion: Edaravone shows remarkable clinical efficacy and safety with no obvious adverse reactions in the treatment of ACH. Therefore, its use is recommended.Keywords: Cerebral haemorrhage, Edaravone, Cerebral edema, C-reactive protein, Interleukin-6, Chinese Stroke Scal
The KAP Evaluation of Intervention on Fall-Induced Injuries among Elders in a Safe Community in Shanghai, China
BACKGROUND: To evaluate the effect of an intervention on fall induced injuries of elderly people in a safe-community in Shanghai and to discuss an intervention model that is proper for the community to generalize. METHODOLOGY/PRINCIPAL FINDINGS: Five neighborhood areas in a Safe Community were purposively selected. All individuals aged 60 years or over in five neighborhoods were prospective participants. From randomly selected prospective households with elders, 2,889 (pre intervention) and 3,021 (post intervention) elderly people were included in the study. Knowledge, Attitude and Practice Model (KAP) questionnaires were used at the pre- and post-intervention phase for fall-induced injury prevention in the community. Descriptive statistics and chi-square tests were used. After the intervention, knowledge about the prevention of fall-induced injuries increased, as did attitudes, beliefs and good behaviors for fall prevention. Behavior modification was most notable with many behavior items changing significantly (p value<0.0001). CONCLUSIONS/ SIGNIFICANCE: The integrated program for reducing fall-related injuries in the community was effective in improving fall prevention among the elderly, but the intervention still needs further improvement
Psychological Capital, Positive Affect, and Organizational Outcomes: A Three-Wave Cross-Lagged Study
Psychological capital (PsyCap) is a higher-order construct comprising hope, efficacy, optimism, and resiliency, which has attracted more and more attention from both academics and practitioners. Despite promising progress made in the PsyCap literature, the underlying mechanisms linking PsyCap to organizational outcomes still need more investigation utilizing longitudinal research design. Moreover, the reciprocal relationships between PsyCap and positive affect require more attention. Therefore, we aim to test the central role of positive affect in the relationships between PsyCap and affective organizational commitment (AOC) on one hand and organizational citizenship behaviour toward organization (OCBO) on the other hand as well as the reciprocal relationships between PsyCap and positive affect in this study. A three-wave longitudinal survey was conducted using a cross-lagged panel design with a one-month time lag between two consecutive waves. Panel data was collected from 208 workers in Beijing, China. The results support the hypothesis that positive affect serves as a mediator in the relationships between PsyCap and OCBO. Moreover, we also find some support for a reciprocal relationship between PsyCap and positive affect. The theoretical and practical implications of the findings are also discussed
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