Knowledge Discovery from Complex Event Time Data with Covariates

In particular engineering applications, such as reliability engineering, complex types of data are encountered which require novel methods of statistical analysis. Handling covariates properly while managing the missing values is a challenging task. These type of issues happen frequently in reliability data analysis. Specifically, accelerated life testing (ALT) data are usually conducted by exposing test units of a product to severer-than-normal conditions to expedite the failure process. The resulting lifetime and/or censoring data are often modeled by a probability distribution along with a life-stress relationship. However, if the probability distribution and life-stress relationship selected cannot adequately describe the underlying failure process, the resulting reliability prediction will be misleading. To seek new mathematical and statistical tools to facilitate the modeling of such data, a critical question to be asked is: Can we find a family of versatile probability distributions along with a general life-stress relationship to model complex lifetime data with covariates? In this dissertation, a more general method is proposed for modeling lifetime data with covariates. Reliability estimation based on complete failure-time data or failure-time data with certain types of censoring has been extensively studied in statistics and engineering. However, the actual failure times of individual components are usually unavailable in many applications. Instead, only aggregate failure-time data are collected by actual users due to technical and/or economic reasons. When dealing with such data for reliability estimation, practitioners often face challenges of selecting the underlying failure-time distributions and the corresponding statistical inference methods. So far, only the Exponential, Normal, Gamma and Inverse Gaussian (IG) distributions have been used in analyzing aggregate failure-time data because these distributions have closed-form expressions for such data. However, the limited choices of probability distributions cannot satisfy extensive needs in a variety of engineering applications. Phase-type (PH) distributions are robust and flexible in modeling failure-time data as they can mimic a large collection of probability distributions of nonnegative random variables arbitrarily closely by adjusting the model structures. In this paper, PH distributions are utilized, for the first time, in reliability estimation based on aggregate failure-time data. To this end, a maximum likelihood estimation (MLE) method and a Bayesian alternative are developed. For the MLE method, an expectation-maximization (EM) algorithm is developed to estimate the model parameters, and the corresponding Fisher information is used to construct the confidence intervals for the quantities of interest. For the Bayesian method, a procedure for performing point and interval estimation is also introduced. Several numerical examples show that the proposed PH-based reliability estimation methods are quite flexible and alleviate the burden of selecting a probability distribution when the underlying failure-time distribution is general or even unknown

The Benefits of Enterprise Resource Planning (ERP) System Implementation in Dry Food Packaging Industry

AbstractThe corporate competitive environment is being liberalized and globalized, therefore the organizations, especially dry food packaging industry, need greater interaction between their stakeholders. One of the problems organizations face to is the segregation of the business functions in an organization. Thus, the business experienced to implement ERP systems for solving this problem. In contrast, the ERP projects have not been effective enough and hence have been unable to achieve all the results envisaged. Therefore, an in depth understanding about the benefits of ERP implementation is needed to ensure the successful system implementation. This study seeks to determine and classify the benefits of ERP system implementation in dry food packaging industry. The methodology of this research comprised of three phases: define the benefits of ERP system implementation from the current literatures, categorize them into strategic, tactical and operational benefits in each business functions in an organization. These ERP benefits are summarized in this paper as a research finding to assist the managers in implementing ERP system successfully

The landscape of non-coding RNAs in the immunopathogenesis of Endometriosis

Endometriosis is a complex disorder that is characterized by the abnormal growth of endometrial-like tissue outside the uterus. It is associated with chronic inflammation, severe pelvic pain, infertility, and significantly reduced quality of life. Although the exact mechanism of endometriosis remains unknown, inflammation and altered immunity are considered key factors in the immunopathogenesis of the disorder. Disturbances of immune responses result in reduced clearance of regurgitated endometrial cells, which elicits oxidative stress and progression of inflammation. Proinflammatory mediators could affect immune cells’ recruitment, fate, and function. Reciprocally, the activation of immune cells can promote inflammation. Aberrant expression of non-coding RNA (ncRNA) in patient and animal lesions could be suggestive of their role in endometriosis establishment. The engagement of these RNAs in regulating diverse biological processes, including inflammatory responses and activation of inflammasomes, altered immunity, cell proliferation, migration, invasion, and angiogenesis are widespread and far-reaching. Therefore, ncRNAs can be identified as a determining candidate regulating the inflammatory responses and immune system. This review aims in addition to predict the role of ncRNAs in the immunopathogenesis of endometriosis through regulating inflammation and altered immunity based on previous studies, it presents a comprehensive view of inflammation role in the pathogenesis of endometriosis

Causal Adversarial Perturbations for Individual Fairness and Robustness in Heterogeneous Data Spaces

As responsible AI gains importance in machine learning algorithms, properties such as fairness, adversarial robustness, and causality have received considerable attention in recent years. However, despite their individual significance, there remains a critical gap in simultaneously exploring and integrating these properties. In this paper, we propose a novel approach that examines the relationship between individual fairness, adversarial robustness, and structural causal models in heterogeneous data spaces, particularly when dealing with discrete sensitive attributes. We use causal structural models and sensitive attributes to create a fair metric and apply it to measure semantic similarity among individuals. By introducing a novel causal adversarial perturbation and applying adversarial training, we create a new regularizer that combines individual fairness, causality, and robustness in the classifier. Our method is evaluated on both real-world and synthetic datasets, demonstrating its effectiveness in achieving an accurate classifier that simultaneously exhibits fairness, adversarial robustness, and causal awareness

Preferred Learning Styles among Ophthalmology Residents: An Iranian Sample

Purpose: This study was performed to assess the learning styles of a sample of Iranian residents through Kolb’s and VARK questionnaires. Methods: In this descriptive-analytical study, 45 ophthalmology residents of Mashhad University of Medical Sciences were enrolled. Kolb’s and VARK questionnaires were provided, and residents were oriented and guided on how to complete them. Results: Forty-three out of the forty-five ophthalmology residents completed the questionnaire (95.5% response rate). The preferred learning style among ophthalmology residents was assimilative (51.2%), followed by convergent (37.2%), accommodative (7.7%), and divergent (4.7%), based on Kolb’s questionnaire. According to the results of the VARK questionnaire, most ophthalmology residents were auditory learners (34.9%), followed by multimodal learners (30.2%). In addition, there was no significant relation between genders, stage of residency, and Kolb’s and VARK learning styles (P > 0.05 for all). Conclusion: The most preferred learning styles of ophthalmology residents were assimilative and auditory. Considering the dominant learning styles of learners and incorporating various teaching methods are recommended to enhance the learning among residents

Current State of Ventilator Setting and Their Relationship with Mortality Rate in Patients under Mechanical Ventilation: A Cross-Sectional Study

Background: Given the importance of implementing lung protective strategies to prevent lung injury caused by ventilators and death of patients, it is necessary to monitor the current condition of hospitals and examine the relationship between the parameters set on the ventilators and patient mortality. This study conducted to determine the current state of ventilator setting and their relationship with mortality rate in patients under mechanical ventilation: a cross-sectional study. Methods: This is a cross-sectional study that was conducted between June to December 2020 in one of the hospitals affiliated to Tehran University of Medical Sciences. The initial tidal volume set on the ventilator was recorded for 304 patients under mechanical ventilation and then, their heights were measured and their tidal volumes were determined based on the standard formula. Other parameters set on the ventilator as well as systolic and diastolic blood pressures of patients were also recorded and their survival rate was investigated. The data was analyzed by SPSS software, using descriptive statistics and logistic regression model. Results: Among patients, who were under mechanical ventilation, 77.6% were hospitalized in intensive care units and the rest were hospitalized in general wards. The mean adjusted tidal volume for patients was 472.91 ± 32.13 ml. The mean peak inspiratory pressure and plateau pressure were 28.00±6.98 and 13.88±4.93 CmH2O, respectively. Also, 37.2% of patients died during the hospitalization. The results of adjusted odds ratio based on multivariate logistic regression model for predictors of mortality rate showed that the variables of patients' age [OR=1.040 (1.019-1.062)], the hospital’s general ward in comparison with the ICU [OR=11.379 (5.130-25.240)] and the peak inspiratory pressure [OR=1.072 (1.007-1.141)] had a direct and significant relationship with mortality rate (in all cases P<0.05). Meanwhile, the plateau pressure [OR=0.886 (0.808 -0.972)] had an inverse and significant relationship with mortality rate (P<0.05). Conclusion: Despite the recommendations regarding lung protective strategies, in some cases, some parameters set in the ventilator are outside the recommended levels, which can effect on patients mortality. So monitoring and controlling the implementation of lung protective strategies and paying attention to controlling pressures set on the ventilator are among measures that should be taken in medical centers in order to prevent lung injuries and maintain patient safety

Fasudil Attenuated 6-OHDA Cytotoxicity in PC12 Cells through Inhibition of JAK/STAT and Apoptosis Pathways

Background: 6-Hydroxydopamine (6-OHDA) is widely used to induce neurotoxicity and investigate the mechanisms of Parkinson disease. 6-OHDA causes cell injury through various mechanisms including oxidative stress, inflammation and apoptosis. The selective Rho-kinase inhibitor, fasudil displays neuroprotective effects in several neurodegenerative disorders. The aim of this study was to assess the protective effect of fasudil in PC12 cytotoxicity induced by 6-OHDA. Methods: PC12 cells were exposed to 5, 10, 25, and 50 µM of fasudil concentrations. After 24 h, the IC50 value of 6-OHDA (150 µM) was added. Twenty-four hours later, the viability of cells was evaluated via MTT assay and the formation of reactive oxygen species (ROS) was measured by the fluorimetric method. At the 50 µM concentration of fasudil, with or without 6-OHDA, the changes of protein levels including STAT3, P-STAT3, JAK2, P-JAK2, and caspase-3 were determined via western blotting. Results: Our results showed that 6-OHDA increased the intracellular level of ROS, reduced cell viability, upregulated p-STAT3/STAT3 and p-JAK2/JAK2 ratios and significantly raised cleaved caspase-3 in comparison to control group. Furthermore, pretreatment of cells with fasudil (50 µM) for 24 h could reverse all changes induced by 6-OHDA. Conclusion: 6-OHDA caused cytotoxicity in PC12 cells through inducing oxidative stress and activating JAK/STAT and apoptosis pathways, while pretreatment with fasudil exhibited protective effect on 6-OHDA-induced neurotoxicity via the inhibition of oxidative stress and prevention of these pathways

High frequency of BRAF V600E mutation in Iranian population ameloblastomas

Ameloblastoma is a common locally invasive but slow-growing neoplasm of the jaws with an odontogenic origin. Association between BRAF V600E mutation and clinicopathologic features and behavior of ameloblastoma remains controversial. This study aimed to evaluate BRAF V600E gene mutation and expression of its related proteins with clinicopathologic parameters in conventional ameloblastoma. 50 Formalin-fixed paraffin-embedded blocks were included in this study. Immunohistochemistry was done using rabbit monoclonal BRAF V600E mutation-specific antibody VE1. Quantitative real-time polymerase chain reaction assay was used for evaluating of BRAF V600E mutation. Expression of BRAF V600E antibody was Positive in 42 out of 50 cases (84%). 46 (92%) out of 50 specimens showed BRAF V600E mutation. There were 13 cases of recurrence (26%). 3 out of 4 cases with negative mutations did not show recurrence. We report the highest frequency (92%) of BRAF V600E mutation in ameloblastomas in the Iranian population. Although there was not a significant association between BRAF V600E?positive immunoexpression and recurrence and clinicopathologic parameters, its high frequency could emphasize its role as a therapeutic marker in the future

Osthole attenuated cytotoxicity induced by 6-OHDA in SH-SY5Y cells through inhibition of JAK/STAT and MAPK pathways

Objective(s): Natural coumarin called osthole is regarded as a medicinal herb with widespread applications in Traditional Chinese Medicine. It has various pharmacological properties, including antioxidant, anti-inflammatory, and anti-apoptotic effects. In some neurodegenerative diseases, osthole also shows neuroprotective properties. In this study, we explored how osthole protects human neuroblastoma SH-SY5Y cells from the cytotoxicity of 6-hydroxydopamine (6-OHDA). Materials and Methods: Using the MTT assay and DCFH-DA methods, respectively, the viability of the cells and the quantity of intracellular reactive oxygen species (ROS) were evaluated. Signal Transducers and Activators of Transcription (STAT), Janus Kinase (JAK), extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and caspase-3 activation levels were examined using western blotting.Results: In SH-SY5Y cells, the results showed that a 24-hour exposure to 6-OHDA (200 µM) lowered cell viability but markedly elevated ROS, p-JAK/JAK, p-STAT/STAT, p-ERK/ERK, p-JNK/JNK ratio, and caspase-3 levels. Interestingly, osthole (100 µM) pretreatment of cells for 24 hr prevented 6-OHDA-induced cytotoxicity by undoing all effects of 6-OHDA. Conclusion: In summary, our data showed that osthole protects SH-SY5Y cells against 6-OHDA-induced cytotoxicity by inhibiting ROS generation and reducing the activity of the JAK/STAT, MAPK, and apoptotic pathways