53 research outputs found

    System Resilience Evaluation and Optimization Considering Epistemic Uncertainty

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    Epistemic uncertainties, caused by data asymmetry and deficiencies, exist in resilience evaluation. Especially in the system design process, it is difficult to obtain enough data for system resilience evaluation and improvement. Mathematics methods, such as evidence theory and Bayesian theory, have been used in the resilience evaluation for systems with epistemic uncertainty. However, these methods are based on subjective information and may lead to an interval expansion problem in the calculation. Therefore, the problem of how to quantify epistemic uncertainty in the resilience evaluation is not well solved. In this paper, we propose a new resilience measure based on uncertainty theory, a new branch of mathematics that is viewed as appropriate for modeling epistemic uncertainty. In our method, resilience is defined as an uncertainty measure that is the belief degree of a system’s behavior after disruptions that can achieve the predetermined goal. Then, a resilience evaluation method is provided based on the operation law in uncertainty theory. To design a resilient system, an uncertain programming model is given, and a genetic algorithm is applied to find an optimal design to develop a resilient system with the minimal cost. Finally, road networks are used as a case study. The results show that our method can effectively reduce cost and ensure network resilience

    Pathological features, clinical presentations and prognostic factors of ovarian large cell neuroendocrine carcinoma: a case report and review of published literature

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    Abstract Background There is no consensus on the optimal chemotherapy regimen and the prognostic factors for ovarian large cell neuroendocrine carcinoma (LCNEC), a rare type of tumor. The objective of the present study is to present the case of a recent encounter of pure ovarian LCNEC and perform a brief review to summarize the clinicopathological features and prognostic factors of 57 cases of LCNEC patients that have been previously reported. Method: case presentation Eligible studies were searched for online and 57 cases with clear follow-up data were found to have been reported. We present the 58th case, which is of a 70-year-old woman with stage IIIc primary pure LCNEC of the ovary. The initial symptom of this patient was abdominal distension (more than 2 months). A recent ultrasound test showed a solid-cystic mass occupying the pelvic and abdominal cavity. She received two courses of cisplatin-etoposide chemotherapy as an adjuvant therapy. No signs of nonclinical or radiological evidence of disease recurrence was found at follow-up examinations during the first 3 months after operation. A retrospective review of these 58 cases was conducted and survival curves were estimated. Using the Kaplan-Meier method. Conclusion The patients included were aged between 18 and 80 years. A Kaplan-Meier survival curve revealed that the median overall survival was 10.000 months, while 26 (44.83%) patients died within 12 months. We compared the overall mean survival time of all patients with that of stage I patients (42.418 vs 42.047 months), which suggests that ovarian LCNEC has a very poor prognosis even at stage I. Mean survival was longer for patients who had undergone postoperative chemotherapy than for those without postoperative chemotherapy (48.082 vs 9.778 months). A small series, such as this, does not provide adequate data to establish a firm correlation between the postoperative chemotherapy and prognosis (p = 0.176). In our review of 58 cases with ovarian LCNEC, prognosis was unfavorable in most cases. Given the rarity of LCNEC, it is highly recommended that a global medical database of ovarian LCNEC and a standard system of diagnosis and treatment is established

    A New Resilience Measure for Supply Chain Networks

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    Currently, supply chain networks can span the whole world, and any disruption of these networks may cause economic losses, decreases in sales and unsustainable supplies. Resilience, the ability of the system to withstand disruption and return to a normal state quickly, has become a new challenge during the supply chain network design. This paper defines a new resilience measure as the ratio of the integral of the normalized system performance within its maximum allowable recovery time after the disruption to the integral of the performance in the normal state. Using the maximum allowable recovery time of the system as the time interval under consideration, this measure allows the resilience of different systems to be compared on the same relative scale, and be used under both scenarios that the system can or cannot restore in the given time. Two specific resilience measures, the resilience based on the amount of product delivered and the resilience based on the average delivery distance, are provided for supply chain networks. To estimate the resilience of a given supply chain network, a resilience simulation method is proposed based on the Monte Carlo method. A four-layered hierarchial mobile phone supply chain network is used to illustrate the resilience quantification process and show how network structure affects the resilience of supply chain networks

    Chlorella vulgaris Extract-Decorated Gold Nanoparticle Hybridized Antimicrobial Hydrogel as a Potential Dressing

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    This study reports a novel design of a moisturizing and antimicrobial hydrogel with injectable properties, using a green solvent (glycerol) as a cross-linking agent and gold nanoparticle reduced by Chlorella extract as an antimicrobial approach. We have synthesized gold nanoparticles (AuNPs) with environmentally friendly and bio-safe properties using Chlorella aqueous extracts (AuNPs@Chlorella). Characterization of the nanoparticles by ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectrum, and transmission electron microscope (TEM) confirmed that spherical AuNPs with the particle size of 10–20 nm were successfully synthesized. An analysis of the enhancement of the stability of gelatin hydrogels by the addition of glycerol and AuNPs was performed by rheometry. In addition, we also used Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) to confirm the good antibacterial activity. Therefore, the as-prepared gelatin–glycerol hydrogels containing AuNPs@Chlorella are most likely promising alternatives for wound healing dressings.</p

    <i>Chlorella vulgaris</i> Extract-Decorated Gold Nanoparticle Hybridized Antimicrobial Hydrogel as a Potential Dressing

    No full text
    This study reports a novel design of a moisturizing and antimicrobial hydrogel with injectable properties, using a green solvent (glycerol) as a cross-linking agent and gold nanoparticle reduced by Chlorella extract as an antimicrobial approach. We have synthesized gold nanoparticles (AuNPs) with environmentally friendly and bio-safe properties using Chlorella aqueous extracts (AuNPs@Chlorella). Characterization of the nanoparticles by ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Raman spectrum, and transmission electron microscope (TEM) confirmed that spherical AuNPs with the particle size of 10–20 nm were successfully synthesized. An analysis of the enhancement of the stability of gelatin hydrogels by the addition of glycerol and AuNPs was performed by rheometry. In addition, we also used Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) to confirm the good antibacterial activity. Therefore, the as-prepared gelatin–glycerol hydrogels containing AuNPs@Chlorella are most likely promising alternatives for wound healing dressings

    Evaluation of Right Ventricle Function in Children With Primary Nephrotic Syndrome

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    We aimed to evaluate right ventricle (RV) function in children with primary nephrotic syndrome (PNS). Methods: RV hemodynamics were evaluated by Doppler echocardiography in 50 children with PNS (aged 2.5–12 years), either at PNS onset (n = 37) or relapse (n = 13), and in 50 normal controls. Heart rate, stroke volume, cardiac output, RV enddiastolic and end-systolic volume, RV ejection fraction, RV end-diastolic pressure, RV peak systolic and end-systolic pressure were determined from pressure-volume loops. The maximal rates of RV pressure upstroke and fall (dP/d tmax and dP/d tmin, respectively) were calculated. Effective pulmonary arterial elastance was calculated as end-systolic pressure divided by stroke volume. Plasma tumor necrosis factor-α (TNF-α) and insulin-like growth factor 1 (IGF-1) were also measured. Results: RV end-diastolic pressure was increased by an average of 20% in 39 of the patients with PNS, whereas RV ejection fraction was reduced by an average of 15% compared with controls (p < 0.05 for both). Cardiac output and stroke volume were maintained, indicating compensation at the expense of increased RV end-diastolic and end-systolic volumes and increased RV filling pressure (p < 0.05). Plasma TNF-α was elevated in patients with PNS (326 ± 117 kU/L vs. 75 ± 23 kU/L, p < 0.05); IGF-1 was similar in PNS patients and controls. Conclusion: Right ventricle function was impaired in children with PNS. The characteristics were unrelated to blood pressure and IGF-1, but may be correlated with TNF-α and disease duration. Further studies are needed to evaluate the etiology and clinical implications of this abnormality

    Impact of perioperative red blood cell transfusion on the prognosis of patients with epithelial ovarian cancer

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    Background: Surgery for advanced ovarian cancer tends to be extensive. We performed an analysis to determine whether perioperative red blood cell transfusion (PRBCT) is associated with a poor prognosis in women with epithelial ovarian cancer (EOC). Methods: Our retrospective analysis included 314 women. The Mann-Whitney rank-sum test and chi-square test were used to analyze the clinical characteristics of the PRBCT and non-PRBCT groups, and Cox proportional hazard models were used for the multivariate analysis. Results: PRBCT was associated with higher relapse and mortality rates in 121 (38.54 %) patients. After multivariate analysis, transfused patients were 1.59 times at risk of death (hazard ratio [HR] = 1.59; 95%CI, 1.12–2.25) and 1.63 times at risk of recurrence (HR = 1.63; 95%CI, 1.22–2.18) than non-transfused patients. Conclusions: PRBCT could prolong hospital stay, and increased hospital costs were significantly associated with increased cancer recurrence and overall mortality in patients with EOC
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