133,421 research outputs found
Stochastically ordered subpopulations and optimal burn-in procedure
No full textBurn-in is a widely used engineering method which is adopted to eliminate defective items before they are shipped to customers or put into the field operation. In the studies of burn-in, the assumption of bathtub shaped failure rate function is usually employed and optimal burn-in procedures are investigated. In this paper, however, we assume that the population is composed of two ordered subpopulations and optimal burn-in procedures are studied in this context. Two types of risks are defined and an optimal burn-in procedure, which minimizes the weighted risks is studied. The joint optimal solutions for the optimal burn-in procedure, which minimizes the mean number of repairs during the field operation, are also investigated.
Recommended from our members
Burn-in policies for products having dormant states
No full textMany systems might have a long time dormant period, during which the systems are not operated. For example, most building services products are installed while a building is constructed, but they are not operated until the building is commissioned. Warranty terms for such products may cover the time starting from their installation times to the end of their warranty periods. Prior to the commissioning of the building, the building services products are protected by warranty although they are not operating. Developing optimal burn-in policies for such products is important when warranty cost is analysed. This paper considers two burn-in policies, which incur different burn-in costs, and have different burn-in effects on the products. A special case about the relationship between the failure rates of the products at the dormant state and at the operating state is presented. Numerical examples compare the mean total warranty costs of these two burn-in policies
Long-term persistance of the pathophysiologic response to severe burn injury.
No full textMain contributors to adverse outcomes in severely burned pediatric patients are profound and complex metabolic changes in response to the initial injury. It is currently unknown how long these conditions persist beyond the acute phase post-injury. The aim of the present study was to examine the persistence of abnormalities of various clinical parameters commonly utilized to assess the degree hypermetabolic and inflammatory alterations in severely burned children for up to three years post-burn to identify patient specific therapeutic needs and interventions.
Nine-hundred seventy-seven severely burned pediatric patients with burns over 30% of the total body surface admitted to our institution between 1998 and 2008 were enrolled in this study and compared to a cohort non-burned, non-injured children. Demographics and clinical outcomes, hypermetabolism, body composition, organ function, inflammatory and acute phase responses were determined at admission and subsequent regular intervals for up to 36 months post-burn. Statistical analysis was performed using One-way ANOVA, Student's t-test with Bonferroni correction where appropriate with significance accepted at p<0.05. Resting energy expenditure, body composition, metabolic markers, cardiac and organ function clearly demonstrated that burn caused profound alterations for up to three years post-burn demonstrating marked and prolonged hypermetabolism, p<0.05. Along with increased hypermetabolism, significant elevation of cortisol, catecholamines, cytokines, and acute phase proteins indicate that burn patients are in a hyperinflammatory state for up to three years post-burn p<0.05.
Severe burn injury leads to a much more profound and prolonged hypermetabolic and hyperinflammatory response than previously shown. Given the tremendous adverse events associated with the hypermetabolic and hyperinflamamtory responses, we now identified treatment needs for severely burned patients for a much more prolonged time
The use of topical sodium hypochlorite in the management of Pseudomonas aeruginosa burn wound infection
No full textThe aim of the study is: 1. To undertake a meta-analysis of Pseudomonas aeruginosa burn wound infection. 2. To undertake a retrospective audit of Pseudomonas aeruginosa burn wound infection at the Red Cross War Memorial Children's Hospital. 3. To investigate the local effects of sodium hypochlorite solutions in Pseudomonas aeruginosa burn wound infection with regards to efficacy and toxicity
Pattern of Childhood Burn Injuries and their Management Outcome at Bugando Medical Centre in Northwestern Tanzania.
No full textBurn injuries constitute a major public health problem and are the leading cause of childhood morbidity and mortality worldwide. There is paucity of published data on childhood burn injuries in Tanzania, particularly the study area. This study was conducted to describe the pattern of childhood burn injuries in our local setting and to evaluate their management outcome. A cross sectional study was conducted at Bugando Medical Centre (in Northwestern Tanzania) over a 3-year period from January 2008 to December 2010. Data was collected using a pre-tested coded questionnaire and statistical analyses performed using SPSS software version 15.0. A total of 342 burned children were studied. Males were mainly affected. Children aged = 2 were the majority accounting for 45.9% of cases. Intentional burn injuries due to child abuse were reported in 2.9% of cases. Scald was the most common type of burns (56.1%). The trunk was the most commonly involved body region (57.3%). Majority of patients (48.0%) sustained superficial burns. Eight (2.3%) patients were HIV positive. Most patients (89.8%) presented to the hospital later than 24 h. The rate of burn wound infection on admission and on 10th day were 32.4% and 39.8% respectively.Staphylococcus aureus were more common on admission wound swabs, with Pseudomonas aeruginosa becoming more evident after 10th day. MRSA was detected in 19.2% of Staphylococcus aureus. Conservative treatment was performed in 87.1% of cases. Surgical treatment mainly skin grafting (65.9%) was performed in 44 (12.9%) of patients. The overall average of the length of hospital stay (LOS) was 22.12 ± 16.62 days. Mortality rate was 11.7%. Using multivariate logistic regression analysis; age of the patient, type of burn, delayed presentation, clothing ignition, %TBSA and severity of burn were found to be significantly associated with LOS (P < 0.001), whereas mortality rate was found to be independently and significantly related to the age of the patient, type of burn, HIV positive with stigmata of AIDS, CD4 count, inhalation injury, %TBSA and severity of burn (P < 0.001). Childhood burn injuries still remain a menace in our environment with virtually unacceptable high morbidity and mortality. There is need for critical appraisal of the preventive measures and management principles currently being practiced
An Analysis of Occupational Burn Injuries in Rhode Island: Workers' Compensation Claims 1998-2002
No full textBackground - upational burns have been determined to be a serious public health concern. The analysis of workplace risks and risk factors associated with burns are critical to developing effective interventions in the future. Methods - This study examined accepted Rhode Island workers' compensation claims (n = 5,619) from 1998 to 2002 to assess the rates and risks of occupational burns. Employment data from the Department of Labor's Current Population Survey (CPS) was used for the estimation of claim rates and shift analyses. Results - The overall burn rate was estimated to be 24.3 per 10,000 workers. The claim rate for workers under 25 years of age was almost double that for all other age groups. The average per-claim disability duration for claims requiring indemnity was 167.9 days and average annual total cost of claims was $1,010,166. The highest claim rate identified was for workers in food service occupations and an increased risk was found for chemical burns among evening and night shift workers. Conclusions - Increased interventions are needed to reduce occupational burns in work settings. Particular diligence should be should address occupational burn hazards in restaurant establishments, and preventative measures aimed at young employees and late shift workers.
Factors Influencing Provision of Care to Hospitalized Peadiatrics Burn Patients: A Qualitative Study Among Nurses in Muhimbili National Hospital Dar es salaam, Tanzania
No full textThe increase number of burn patients‘ admission in Muhimbili National Hospital indicated that burn injury is still a problem in our setting. In July 2011 up to June 2012 a total of 6135 paediatrics patients were admitted in MNH due to various diseases of which 319 patients were admitted due to burn injury. This is equal to 5.2% of all paediatrics admission (unpublished report). However hospital management made good coordination and availability of working equipments in order to archive optimal care for paediatric burn patients. Even though Health care providers especially nurse were facing some difficulties in provision of burn care. The main objective of this study was to explore nurses‘ perceptions on factors influencing provision of care to pediatric burn patients among nurses at Muhimbili National Hospital. Five in depth interviews were conducted in order to explore nurses‘ perception on factors that may influence provision of nursing care to hospitalized pediatric burn patients. This study was conducted from May 2012 to June 2012 in MNH. Simple observation method was used to complement data obtained through in-depth interviews. The study informants were sampled by using purposive sampling procedure. Data was analyzed by using content analysis approach. Findings The present study revealed two major categories which include motivating factors and barriers in provision of burn care. Participants described the use of closed method of wound dressing as an important skill that accelerates healing, decrease risk of wound contamination and decreased number of contractures. Presence of team work in burn care, facilitated patients recovery through reviewed and discussed management of patients as a team. Availability of equipments helped nurses to perform nursing care smoothly. Furthermore, participants felt gratified and increased work performance when they saw patients who sustained very severe burn injury recovering and going back home. Despite the fact that burn care was found somehow successfully in Muhimbili National Hospital (MNH), participants revealed several factors that hindered provision of care. These factors include limited resources, patient workload, and lack of standard skills. Participants described that there were limited human and non human resources, such as shortage of staffing which resulted into overworking, physical and emotional exhaustion among nurses, lack of water which is the mainstay of infection prevention control, lack of specimen equipment like pus swab. Since burn patient are at risk of infection therefore they need to take pus swab frequently. Nevertheless, participants expressed that they lack standard skills on burn care since there was no special training on burn care. Instead they were teaching themselves in the sense that experienced nurses in burn unit were teaching new nurses who came to work in burn unit. The finding of this study revealed that there are both positively and negatively factors that influence provision of burn care. Positive factor (motivation) needed to be maintained but action is required to be taken in order to reduce negative factors. More public health enlightenment is needed on prevention and initial intervention for burns in children. Community need to be aware that prevention of burn should be a priority since caring for burnt patient is very expensive. Further studies are needed in large population since this information is not conclusive to factors influence burn care in Tanzania.\ud
\u
Classifying Weak, and Strong Components using ROC Analysis with Application to Burn-in
No full textAny population of components produced might be composed of two sub-populations: weak components are less reliable, and deteriorate faster whereas strong components are more reliable, and deteriorate slower. When selecting an approach to classifying the two sub-populations, one could build a criterion aiming to minimize the expected mis-classification cost due to mis-classifying weak (strong) components as strong (weak). However, in practice, the unit mis-classification cost, such as the cost of mis-classifying a strong component as weak, cannot be estimated precisely. Minimizing the expected mis-classification cost becomes more difficult. This problem is considered in this paper by using ROC (Receiver Operating Characteristic) analysis, which is widely used in the medical decision making community to evaluate the performance of diagnostic tests, and in machine learning to select among categorical models. The paper also uses ROC analysis to determine the optimal time for burn-in to remove the weak population. The presented approaches can be used for the scenarios when the following information cannot be estimated precisely: 1) life distributions of the sub-populations, 2) mis-classification cost, and 3) proportions of sub-populations in the entire population
The use of a modified tonometer in burn scar therapy
No full textWe report on the use of a modified Schiotz tonometer to evaluate the effects of therapies on burn scars. It is now possible to quantify the course of cicatrization with tonometry. Because tonometry affords a precise evaluation of burn scar diagnosis and prognosis, it is possible to avoid arbitrary clinical evaluation of the burn scarring process
Burn-induced apoptotic change was mitigated by iNOS deficiency.
No full textAt 3 days after burn or sham-burn, mRNA levels of Bax and FasL, DNA fragmentation and cleaved caspase-3 were increased by burn injury in wild-type (WT) mice, all of which were mitigated in iNOS knockout (iNOS KO) mice. mRNA levels of Fas was not significantly altered by burn or iNOS deficiency. **P<0.01, ***P<0.001 vs. WT-Sham and iNOS KO-Sham, §P<0.05, §§P<0.01, §§§P<0.001 vs. WT-Burn, NS: not significant. n = 3 mice per group for Sham; n = 5 mice per group for Burn.</p
- …
