Search results for: end stage renal failure

Authors: Baby Tabassum, Priya Bajaj

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Cadmium is the second most hazardous heavy metal occurring in both elemental as well as compound forms. It is a highly toxic metal with a very high bio-concentration factor (BCF>100). WHO permitted groundwater cadmium concentration is 0.005 mg/L only, but reality is far away from this limit. A number of natural and anthropogenic industrial activities contribute to the spread of cadmium into the environment. The present study had been designated to find out the renal changes at functional level after cadmium intoxication and protection against these changes offered by Mentha piperata. For the purpose, albino rats were selected as the model organism. Cadmium significantly increases the serum level of serum proteins and nitrogenous wastes showing reduced filtration rate of kidneys. Pretreatment with Mentha piperata leaf extract causes significant retention of these levels to normalcy. These findings conclude that Cadmium exposure affects renal functioning but Mentha could prevent it, proving its nephro-protective potential against heavy metal toxicity.

Keywords: albino rat, cadmium, Mentha piperata, nephrotoxicity

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Authors: Shedy Maharani Nariswari, Prima Agustia Nova, I. Made Kariasa

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Background. Heart Failure (HF) is a chronic and progressive condition associated with significant morbidity, mortality, health care expenditures, and a high readmission rate over the years. Self‐care is essential to manage chronic heart failure in the long term, and it is related to better outcomes and can enhance the quality of life. Objective. The aims of this study were to describe the relationship between self-care behavior and quality of life among heart failure patients in East Jakarta, Indonesia. Methods. This study used a correlational-descriptive design with a cross-sectional study, the sampling method used purposive sampling method. Self-care was measured using Self-care Heart Failure Index version 6.2, and quality of life was measured using The Minnesota Living with Heart Failure. Pearson correlation and Spearman-rho correlations are used to analyze the data. Results. We recruited 103 patients with HF in both outpatient and inpatient ward: mean age 59.26 ± 11.643 years, 63.1% male. Patients with higher levels of education were associated with higher self-care maintenance (p= 0.007). The patient's average quality of life is quite high, with a score of 72,07 ± 16,89. There were a significant relationship among self-care maintenance (r=0,305, p=0,001), self-care management (r=0,330, p=0,001), and self-care confidence (r=0,335, p=0,001) towards the quality of life. Most participants have inadequate self-care maintenance, self-care management, and self-care confidence (score < 70), while the score of quality of life is categorized as poor. Conclusion. The self-care behaviors were limited among patients living with HF in Indonesia yet was associated with better quality of life. It is necessary to promote health related to knowledge and adherence to self-care behavior so that it can improve the quality of life of heart failure patients. This study can be used as a reference to promote self-care among patients with heart failure, it can help to enhance their quality of life.

Keywords: heart failure, self-care maintenance, self-care management, self-care confidence, quality of life

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Authors: Hamid Hatami

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This experiment was included two cultivars i.e. Habbit and L17 (Main factor) with six fertilizer treatments i.e. control, seed inoculated with rhyzobium, base nitrogen + top-dress urea at R2 stage, base nitrogen + seed inoculated with rhyzobium + top-dress nitrogen at R2 stage, seed treated with humax + top-dress humax at R2 stage, base nitrogen + seed treated with humax + top-dress humax at R2 stage (sub factors ), as split-plot on the basis of RCBD with 3 replications at 2014. Treatment fertilizer of base nitrogen + seed treated with humax + top- dress humax at R2 stage and base nitrogen + top-dress urea in R2 stage had a significant superiority than the other fertilizer treatment in biological yield. L17 and Habbit with base nitrogen + seed treated with humax + top-dress humax in R2 stage and yield economical 5600 and 5767 kg/ha respectively, showed the most economical yield and Habbit cultivar with control and economical yield 3085 kg/ha showed the least economical yield among all the treatments. Results showed that fertilizer treatment of base nitrogen + seed treated with humax + top-dress humax in R2 stage and Habbit variety were suitable in this study.

Keywords: soybean, humax, rhyzobium, habbit

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Authors: B. Lee, B. H. Choi

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The loss of safety for reservoirs brought about by climate change and facility aging leads to reservoir failures, which results in the loss of lives and property damage in downstream areas. Therefore, it is necessary to provide a reservoir failure alert system for downstream residents to detect the early signs of failure (with sensors) in real-time and perform safety management to prevent and minimize possible damage. 10 case studies were carried out to verify the water level management criteria of four levels (attention, caution, alert, serious). Peak changes in water level data were analysed. The results showed that ‘Caution’ and ‘Alert’ were closed to 33% and 66% of difference in level between flood water level and full water level. Therefore, it is adequate to use initial water level management criteria of reservoir failure alert system for the first year. Acknowledgment: This research was supported by a grant (2017-MPSS31-002) from 'Supporting Technology Development Program for Disaster Management' funded by the Ministry of the Interior and Safety(MOIS)

Keywords: alert system, management criteria, reservoir failure, sensor

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Authors: Srinivasan Chandrasekaran, Manda Hari Venkata Ramachandra Rao

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Increase in the oil and gas exploration in ultra deep-water demands an adaptive structural form of the platform. Triceratops has superior motion characteristics compared to that of the Tension Leg Platform and Single Point Anchor Reservoir platforms, which is well established in the literature. Buoyant legs that support the deck are position-restrained to the sea bed using tethers with high axial pretension. Environmental forces that act on the platform induce dynamic tension variations in the tethers, causing the failure of tethers. The present study investigates the dynamic response behavior of the restraining system of the platform under the failure of a single tether of each buoyant leg in high sea states. Using the rain-flow counting algorithm and the Goodman diagram, fatigue damage caused to the tethers is estimated, and the fatigue life is predicted. Results shows that under failure conditions, the fatigue life of the remaining tethers is quite alarmingly low.

Keywords: fatigue life, pm spectrum, rain flow counting, triceratops, failure analysis

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Authors: Piyas Palit, Urbi Pal, Jitendra Mathur, Santanu Das

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Bearing is an important machinery part in the industry. When bearings fail to meet their expected life the consequences are increased downtime, loss of revenue and missed the delivery. This article describes the failure of a gearbox bearing in rolling contact fatigue. The investigation consists of visual observation, chemical analysis, characterization of microstructures using optical microscopes and hardness test. The present study also considers bearing life as well as the operational condition of bearings. Surface-initiated rolling contact fatigue, leading to a surface failure known as pitting, is a life-limiting failure mode in many modern machine elements, particularly rolling element bearings. Metallography analysis of crack propagation, crack morphology was also described. Indication of fatigue spalling in the ferrography test was also discussed. The analysis suggested the probable reasons for such kind of failure in operation. This type of spalling occurred due to (1) heavier external loading condition or (2) exceeds its service life.

Keywords: bearing, rolling contact fatigue, bearing life

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Authors: Soudabeh Shemehsavar

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In this paper, we consider the situation under a life test, in which the failure time of the test units are not related deterministically to an observable stochastic time varying covariate. In such a case, the joint distribution of failure time and a marker value would be useful for modeling the step stress life test. The problem of accelerating such an experiment is considered as the main aim of this paper. We present a step stress accelerated model based on a bivariate Wiener process with one component as the latent (unobservable) degradation process, which determines the failure times and the other as a marker process, the degradation values of which are recorded at times of failure. Parametric inference based on the proposed model is discussed and the optimization procedure for obtaining the optimal time for changing the stress level is presented. The optimization criterion is to minimize the approximate variance of the maximum likelihood estimator of a percentile of the products’ lifetime distribution.

Keywords: bivariate normal, Fisher information matrix, inverse Gaussian distribution, Wiener process

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Authors: Bárbara Durão, Pedro Almeida, David Ramilo, André Meneses, Rute Canejo-Teixeira

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The importance of quality of life (QoL) assessment in veterinary medicine is an integral part of patient care. This is especially true in cases of chronic diseases, such as chronic kidney disease (CKD), where the ever more advanced treatment options prolong the patient’s life. Whether this prolongment of life comes with an acceptable quality of life remains has been called into question. The aim of this study was to evaluate the relationship between CKD disease biomarkers and QoL in cats. Thirty-seven cats diagnosed with CKD and with no known concurrent illness were enrolled in an observational study. Through the course of several evaluations, renal biomarkers were assessed in blood and urine samples, and owners retrospectively described their cat’s quality of life using a validated instrument for this disease. Correlations between QoL scores (AWIS) and the biomarkers were assessed using Spearman’s rank test. Statistical significance was set at p-value < 0.05, and every serial sample was considered independent. Thirty-seven cats met the inclusion criteria, and all owners completed the questionnaire every time their pet was evaluated, giving a total of eighty-four questionnaires, and the average-weighted-impact-score was –0.5. Results showed there was a statistically significant correlation between the quality of life and most of 17 the studied biomarkers and confirmed that CKD has a negative impact on QoL in cats especially due to the management of the disease and secondary appetite disorders. To our knowledge, this is the attempt to assess the correlation between renal biomarkers and QoL in cats. Our results reveal a strong potential of this type of approach in clinical management, mainly in situations where it is not possible to measure biomarkers. Whilst health-related QoL is a reliable predictor of mortality and morbidity in humans; our findings can help improve the clinical practice in cats with CKD.

Keywords: chronic kidney disease, biomarkers, quality of life, feline

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Authors: Tareq Oshan

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Facility location and size decisions are important to any company because they affect profitability and success. However, warehouses are exposed to various risks of failure that affect their activity. This paper presents a mixed-integer non-linear mathematical model that can be used to determine optimal warehouse locations and sizes, which warehouses to fortify, and which branches should be assigned to specific warehouses when there is a risk of warehouse failure. Every branch is assigned to a fortified primary warehouse or a nonfortified primary warehouse and a fortified backup warehouse. The standard method and an introduced method, based on the average probabilities, for linearizing this mathematical model were used. A Canadian case study was used to demonstrate the developed mathematical model, followed by some sensitivity analysis.

Keywords: supply chain network design, fortified warehouse, mixed-integer mathematical model, warehouse failure risk

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Authors: Sameer A. Pathan, Biswadev Mitra, Salman Mirza, Umais Momin, Zahoor Ahmed, Lubna G. Andraous, Dharmesh Shukla, Mohammed Y. Shariff, Magid M. Makki, Tinsy T. George, Saad S. Khan, Stephen H. Thomas, Peter A. Cameron

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Study objective: Emergency physician’s (EP) ability to identify hydronephrosis on point-of-care ultrasound (POCUS) has been assessed in the past using CT scan as the reference standard. We aimed to assess EP interpretation of POCUS to identify and grade the hydronephrosis in a direct comparison with the consensus-interpretation of POCUS by radiologists, and also to compare the EP and radiologist performance using CT scan as the criterion standard. Methods: Using data from a POCUS databank, a prospective interpretation study was conducted at an urban academic emergency department. All POCUS exams were performed on patients presenting with renal colic to the ED. Institutional approval was obtained for conducting this study. All the analyses were performed using Stata MP 14.0 (Stata Corp, College Station, Texas). Results: A total of 651 patients were included, with paired sets of renal POCUS video clips and the CT scan performed at the same ED visit. Hydronephrosis was reported in 69.6% of POCUS exams by radiologists and 72.7% of CT scans (p=0.22). The κ for consensus interpretation of POCUS between the radiologists to detect hydronephrosis was 0.77 (0.72 to 0.82) and weighted κ for grading the hydronephrosis was 0.82 (0.72 to 0.90), interpreted as good to very good. Using CT scan findings as the criterion standard, Eps had an overall sensitivity of 81.1% (95% CI: 79.6% to 82.5%), specificity of 59.4% (95% CI: 56.4% to 62.5%), PPV of 84.3% (95% CI: 82.9% to 85.7%), and NPV of 53.8% (95% CI: 50.8% to 56.7%); compared to radiologist sensitivity of 85.0% (95% CI: 82.5% to 87.2%), specificity of 79.7% (95% CI: 75.1% to 83.7%), PPV of 91.8% (95% CI: 89.8% to 93.5%), and NPV of 66.5% (95% CI: 61.8% to 71.0%). Testing for a report of moderate or high degree of hydronephrosis, specificity of EP was 94.6% (95% CI: 93.7% to 95.4%) and to 99.2% (95% CI: 98.9% to 99.5%) for identifying severe hydronephrosis alone. Conclusion: EP POCUS interpretations were comparable to the radiologists for identifying moderate to severe hydronephrosis using CT scan results as the criterion standard. Among patients with moderate or high pre-test probability of ureteric calculi, as calculated by the STONE-score, the presence of moderate to severe (+LR 6.3 and –LR 0.69) or severe hydronephrosis (+LR 54.4 and –LR 0.57) was highly diagnostic of the stone disease. Low dose CT is indicated in such patients for evaluation of stone size and location.

Keywords: renal colic, point-of-care, ultrasound, bedside, emergency physician

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Authors: S. Candamano, A. Iorfida, L. Pagnotta, F. Crea

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Basalt fabric reinforced cementitious composites (FRCM) have attracted great attention because they result in being effective in structural strengthening and eco-efficient. In this study, authors investigate their mechanical behavior when an alkali-activated binder, with tuned properties and containing high amounts of industrial by-products, such as ground granulated blast furnace slag, is used. Reinforcement is made up of a balanced, coated bidirectional fabric made out of basalt fibres and stainless steel micro-wire, with a mesh size of 8x8 mm and an equivalent design thickness equal to 0.064 mm. Mortars mixes have been prepared by maintaining constant the water/(reactive powders) and sand/(reactive powders) ratios at 0.53 and 2.7 respectively. Tensile tests were carried out on composite specimens of nominal dimensions equal to 500 mm x 50 mm x 10 mm, with 6 embedded rovings in the loading direction. Direct shear tests (DST), aimed to the stress-transfer mechanism and failure modes of basalt-FRCM composites, were carried out on brickwork substrate using an externally bonded basalt-FRCM composite strip 10 mm thick, 50 mm wide and a bonded length of 300 mm. Mortars exhibit, after 28 days of curing, a compressive strength of 32 MPa and a flexural strength of 5.5 MPa. Main hydration product is a poorly crystalline CASH gel. The constitutive behavior of the composite has been identified by means of direct tensile tests, with response curves showing a tri-linear behavior. The first linear phase represents the uncracked (I) stage, the second (II) is identified by crack development and the third (III) corresponds to cracked stage, completely developed up to failure. All specimens exhibit a crack pattern throughout the gauge length and failure occurred as a result of sequential tensile failure of the fibre bundles, after reaching the ultimate tensile strength. The behavior is mainly governed by cracks development (II) and widening (III) up to failure. The main average values related to the stages are σI= 173 MPa and εI= 0.026% that are the stress and strain of the transition point between stages I and II, corresponding to the first mortar cracking; σu = 456 MPa and εu= 2.20% that are the ultimate tensile strength and strain, respectively. The tensile modulus of elasticity in stage III is EIII= 41 GPa. All single-lap shear test specimens failed due to composite debonding. It occurred at the internal fabric-to-matrix interface, and it was the result of fracture of the matrix between the fibre bundles. For all specimens, transversal cracks were visible on the external surface of the composite and involved only the external matrix layer. This cracking appears when the interfacial shear stresses increase and slippage of the fabric at the internal matrix layer interface occurs. Since the external matrix layer is bonded to the reinforcement fabric, it translates with the slipped fabric. Average peak load around 945 N, peak stress around 308 MPa, and global slip around 6 mm were measured. The preliminary test results allow affirming that Alkali Activated Binders can be considered a potentially valid alternative to traditional mortars in designing FRCM composites.

Keywords: alkali activated binders, basalt-FRCM composites, direct shear tests, structural strengthening

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Authors: Jaleh Mohammad Aliha, Rezvan Razazi, Nasim Naderi

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Introduction: Despite the progress in new effective drugs in the treatment of heart failure, the disease still accompanied with frequent hospitalization, impaired quality of life, early mortality and significant economic burden. Patients with chronic disease and consequently patients with heart failure need the knowledge and optimal health literacy to improve the quality of life and minimize the rate of rehopitalizatio. So, considering to importance of knowledge and health literacy in this patients as well as contradictory literature, this study conducted to investigate the relationship between health literacy and Knowledge of heart failure with rehospitalization in patients with heart failure admitted to heart failure clinic in Rajai Heart center in 1394. Methods: The cross-sectional method with convenience sampling method was used in this study. After obtaining the necessary permissions from the ethics committee and the Shahid Rajai Heart center, 238 patients who were older than 18 years and had ejection fraction 35% or less with the ability to read and write and lack of psychiatric, neurological and cognitive disorders and signed the informed consent were recruited. Data collection were perfomed through demographic data questionnaire, short standard health literacy questionnaire 'Short-TOFHLA-16' and Vanderwall (2005) knowledge of heart failure questionnaire. Reliability was assessed by internal consistency method and Cronbach's alpha for both questionnaires was more than 0.7. Then data were analysed by SPSS-20 with descriptive statistic and analytical statistic such as T-test, Chi-square and ANOVA. Results: The majority of patients were male (66%), married (80%) and had age between 50 to 70 years old (42%). The majority of studied men and women have good health literacy and About half of them have adequate knowledge about heart failure. Fisher's exact test showed that there was a significant statistical correlation between health literacy and knowlegh about heart failure. In other words, higher health literacy associated with more knowledge about their condition. Also findings showed that there was no significant statistical correlation between health literacy and knowledge about heart failure and frequency of CCU and emergency admissions. Conclusion: The study results showed that the higher health literacy, associated with the greater knowledge about heart failure and patients' perception about caring recommendations and disease outcomes. Therefore, the knowledge about heart failure and factors which related to severity of the disease, is the important issue to problem identification and treatment and reduction of rehospitalization.

Keywords: health literacy, heart failure, knowlegde, rehospitalization

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Authors: S. P. Bansal, Mukesh Kumar Sharma, Ankit Prabhakar

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Luhri Hydroelectric Project Stage-I (210 MW) is a run of the river type development with a dam toe surface powerhouse (122m long, 50.50m wide, and 65.50m high) on the right bank of river Satluj in Himachal Pradesh, India. The project is located in the inner lesser Himalaya between Dhauladhar Range in the south and higher Himalaya in the north in the seismically active region. At the project, the location river is confined within narrow V-shaped valleys with little or no flat areas close to the river bed. Nearly 120m high cut slopes behind the powerhouse are proposed from the powerhouse foundation level of 795m to ± 915m to accommodate the surface powerhouse. The stability of 120m high cut slopes is a prime concern for the reason of risk involved. The slopes behind the powerhouse will be excavated in mainly in augen gneiss, fresh to weathered in nature, and biotite rich at places. The foliation joints are favorable and dipping inside the hill. Two valleys dipping steeper joints will be encountered on the slopes, which can cause instability during excavation. Geological exploration plays a vital role in designing and optimization of cut slopes. SWEDGE software has been used to analyze the geometry and stability of surface wedges in cut slopes. The slopes behind powerhouse have been analyzed in three zones for stability analysis by providing a break in the continuity of cut slopes, which shall provide quite substantial relief for slope stabilization measure. Pseudo static analysis has been carried out for the stabilization of wedges. The results indicate that many large wedges are forming, which have a factor of safety less than 1. The stability measures (support system, bench width, slopes) have been planned so that no wedge failure may occur in the future.

Keywords: cut slopes, geotechnical investigations, Himalayan geology, surface powerhouse, wedge failure

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Authors: F. Bouzeboudja, K. Ait-Tahar

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The method of strengthening of concrete works by composite materials is a practice which knows currently an important development. From this perspective, we propose to make a contribution to the analysis of the behavior of concrete slabs reinforced with composite fabrics, arranged in parallel folds according to the thickness of the slab. The analysis of experimentally obtained modes of failure confirms, generally, that the ruin of the structure occurs essentially by punching. Accordingly, our work is directed to the analysis of the behavior of reinforced slabs towards the punching. An experimental investigation is realized. For that purpose, a set of trial specimens was made. The reinforced specimens are subjected to an essay of punching, by making vary the direction of the eccentricity. The first experimental results show that the ultimate loads, as well as the transition from the flexion failure mode to the punching failure mode, are governed essentially by the eccentricity.

Keywords: composites, concrete slabs, failure, laminate, punching

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Authors: Ariful Islam, Showkat Ahmad Lone

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The Mukherjee-Islam Model is commonly used as a simple life time distribution to assess system reliability. The model exhibits a better fit for failure information and provides more appropriate information about hazard rate and other reliability measures as shown by various authors. It is possible to introduce a location parameter at a time (i.e., a time before which failure cannot occur) which makes it a more useful failure distribution than the existing ones. Even after shifting the location of the distribution, it represents a decreasing, constant and increasing failure rate. It has been shown to represent the appropriate lower tail of the distribution of random variables having fixed lower bound. This study presents the reliability computations and probability weighted moment estimation of three parameter model. A comparative analysis is carried out between three parameters finite range model and some existing bathtub shaped curve fitting models. Since probability weighted moment method is used, the results obtained can also be applied on small sample cases. Maximum likelihood estimation method is also applied in this study.

Keywords: comparative analysis, maximum likelihood estimation, Mukherjee-Islam failure model, probability weighted moment estimation, reliability

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Authors: Atitallah Sofien, Bouyahia Olfa, Attar Souleima, Missaoui Nada, Ben Rabeh Rania, Yahyaoui Salem, Mazigh Sonia, Boukthir Samir

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Introduction: Ciliopathies are a spectrum of diseases that have in common a defect in the synthesis of ciliary proteins. It is a rare cause of neonatal cholestasis. Clinical presentation varies extremely, and the main affected organs are the kidneys, liver, and pancreas. Methodology: This is a descriptive case report of a newborn who was admitted for exploration of neonatal cholestasis in the Paediatric Department C at the Children’s Hospital of Tunis, where the investigations concluded with a rare genetic mutation. Results: This is the case of a newborn male with no family history of hepatic and renal diseases, born to consanguineous parents, and from a well-monitored uneventful pregnancy. He developed jaundice on the second day of life, for which he received conventional phototherapy in the neonatal intensive care unit. He was admitted at 15 days for mild bronchiolitis. On clinical examination, intense jaundice was noted with normal stool and urine colour. Initial blood work showed an elevation in conjugated bilirubin and a high gamma-glutamyl transferase level. Transaminases and prothrombin time were normal. Abdominal sonography revealed hepatomegaly, splenomegaly, and undifferentiated renal cortex with bilateral medullar micro-cysts. Kidney function tests were normal. The infant received ursodeoxycholic acid and vitamin therapy. Genetic testing showed a homozygous mutation in the DCDC2 gene that hadn’t been documented before confirming the diagnosis of renal-hepatic ciliopathy. The patient has regular follow-ups, and his conjugated bilirubin and gamma-glutamyl transferase levels have been decreasing. Conclusion: Genetic testing has revolutionized the approach to etiological diagnosis in pediatric cholestasis. It enables personalised treatment strategies to better enhance the quality of life of patients and prevent potential complications following adequate long-term monitoring.

Keywords: cholestasis, newborn, ciliopathy, DCDC2, genetic

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Authors: Loai Ben Naji, Osama M. Ibrahim, Khaled J. Al-Fadhalah

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The objective of this paper is to investigate the formation and adhesion of a protective aluminum-oxide (Al₂O₃, alumina) layer on the surface of Iron-Chromium-Aluminum Alloy (Fe-Cr-Al) sintered-metal-fibers. The oxide-scale layer was developed via multi-stage thermal oxidation at 930 ^oC for 1 hour, followed by 1 hour at 960 ^oC, and finally at 990 ^oC for 2 hours. Scanning Electron Microscope (SEM) images show that the multi-stage thermal oxidation resulted in the formation of predominantly Al₂O₃ platelets-like and whiskers. SEM images also reveal non-uniform oxide-scale growth on the surface of the fibers. Furthermore, peeling/spalling of the alumina protective layer occurred after minimum handling, which indicates weak adhesion forces between the protective layer and the base metal alloy.  Energy Dispersive Spectroscopy (EDS) analysis of the heat-treated Fe-Cr-Al sintered-metal-fibers confirmed the high aluminum content on the surface of the protective layer, and the low aluminum content on the exposed base metal alloy surface. In conclusion, the failure of the oxide-scale protective layer exposes the base metal alloy to further oxidation, and the fragile non-uniform oxide-scale is not suitable as a support for catalysts.

Keywords: high-temperature oxidation, iron-chromium-aluminum alloy, alumina protective layer, sintered-metal-fibers

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Authors: B. Engel, Sara Salman Hassan Al-Maeeni

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Human consumption of the Earth's resources increases the need for a sustainable development as an important ecological, social, and economic theme. Re-engineering of machine tools, in terms of design and failure analysis, is defined as steps performed on an obsolete machine to return it to a new machine with the warranty that matches the customer requirement. To understand the future fatigue behavior of the used machine components, it is important to investigate the possible causes of machine parts failure through design, surface, and material inspections. In this study, the failure modes of the shaft of the rotary draw bending machine are inspected. Furthermore, stress and deflection analysis of the shaft subjected to combined torsion and bending loads are carried out by an analytical method and compared with a finite element analysis method. The theoretical fatigue strength, correction factors, and fatigue life sustained by the shaft before damaged are estimated by creating a stress-cycle (S-N) diagram. In conclusion, it is seen that the shaft can work in the second life, but it needs some surface treatments to increase the reliability and fatigue life.

Keywords: failure analysis, fatigue life, FEM analysis, shaft, stress analysis

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Authors: Kim Duc Hoang, Hyeong Joon Ahn

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Residual vibration of the system base due to a high-acceleration motion of a stage may reduce life and productivity of the manufacturing device. Although a passive RFC can reduce vibration of the system base, spring or dummy mass should be replaced to tune performance of the RFC. In this paper, we develop a novel concept of the passive RFC mechanism for a linear motor motion stage using pre-compressed springs. Dynamic characteristic of the passive RFC can be adjusted by pre-compression of the spring without exchanging the spring or dummy mass. First, we build a linear motor motion stage with pre-compressed springs. Then, the effect of the pre-compressed spring on the passive RFC is investigated by changing both pre-compressions and stiffness of springs. Finally, the effectiveness of the passive RFC using pre-compressed springs was verified with both simulations and experiments.

Keywords: linear motor motion stage, residual vibration, passive RFC, pre-compressed spring

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Authors: Rafiqul Hasan, A. S. M. Tanim Anwar, Mohammad Azizul Hakim

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Background: Chronic kidney disease (CKD) is a major public health problem that continues to increase in prevalence globally. The prevalence of chronic kidney disease is increasing day by day in low to middle income countries (LMICs). People living in LMICs have the highest need for renal replacement therapy (RRT) despite they have lowest access to various modalities of treatment. As continuous ambulatory peritoneal dialysis (CAPD) does not require advanced technologies, very much infrastructure, dialysis staff support, it should be an ideal form of RRT in LMICs, particularly for those living in remote areas. To authors knowledge there was scarcity of data regarding CAPD performance in remote area of Bangladesh. This study was aimed to report the characteristics and outcomes of CAPD in ESRD patients lived in least developed area of Bangladesh. Methods: This prospective study was conducted in Cox’sbazar Medical College Hospital, Cox’sbazar and Parkview hospital Ltd, Chattogram, Bangladesh. Data were collected by questionnaire from the patients of any age with end-stage renal disease (ESRD) who underwent CAPD in 2018–2021. The baseline characteristics, PD-related complication as well as patient and technique survivals were analyzed. Results: Out of 31 patients who underwent CAPD, 18 (58%) were male on the age range of 15–79 years. The mean follow-up duration was 18 months. Mortality was inversely related with the EF of echocardiography. The peritonitis rate was 0.48 episodes per patient per year. The 1, 3 and 4-year patient survival rates were 64.34% (95% CI = 52.5–81.5), 23.79% (95% CI = 17.9 – 57.4) and 3.22% (95% CI = 31.2–77.5) respectively. Conclusions: In this study, CAPD performance was poorer than usual reference. Cardiac compromised patient and inappropriate dwell might be the main contributing factors behind this scenario. The peritonitis rate was nearly similar to that of developed countries. CAPD was cost effective than HD in remote area. Some accessible measures may be taken to make CAPD a more acceptable RRT modality with improved outcomes in poor socioeconomic backgrounds.

Keywords: dialysis cost, peritoneal dialysis, peritonitis, CAPD, least developed area, remote area, Bangladesh

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Authors: Ayesha Waqar Khan, Mariam Altaf, Jamil Ahmad, Shaheen Shahzad

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Kidney fibrosis is an anticipated outcome of possibly all types of progressive chronic kidney disease (CKD). Epithelial-mesenchymal transition (EMT) signaling pathway is responsible for production of matrix-producing fibroblasts and myofibroblasts in diseased kidney. In this study, a discrete model of TGF-beta (transforming growth factor) and CTGF (connective tissue growth factor) was constructed using Rene Thomas formalism to investigate renal fibrosis turn over. The kinetic logic proposed by Rene Thomas is a renowned approach for modeling of Biological Regulatory Networks (BRNs). This modeling approach uses a set of constraints which represents the dynamics of the BRN thus analyzing the pathway and predicting critical trajectories that lead to a normal or diseased state. The molecular connection between TGF-beta, Smad 2/3 (transcription factor) phosphorylation and CTGF is modeled using GenoTech. The order of BRN is CTGF, TGF-B, and SMAD3 respectively. The predicted cycle depicts activation of TGF-B (TGF-β) via cleavage of its own pro-domain (0,1,0) and presentation to TGFR-II receptor phosphorylating SMAD3 (Smad2/3) in the state (0,1,1). Later TGF-B is turned off (0,0,1) thereby activating SMAD3 that further stimulates the expression of CTGF in the state (1,0,1) and itself turns off in (1,0,0). Elevated CTGF expression reactivates TGF-B (1,1,0) and the cycle continues. The predicted model has generated one cycle and two steady states. Cyclic behavior in this study represents the diseased state in which all three proteins contribute to renal fibrosis. The proposed model is in accordance with the experimental findings of the existing diseased state. Extended cycle results in enhanced CTGF expression through Smad2/3 and Smad4 translocation in the nucleus. The results suggest that the system converges towards organ fibrogenesis if CTGF remains constructively active along with Smad2/3 and Smad 4 that plays an important role in kidney fibrosis. Therefore, modeling regulatory pathways of kidney fibrosis will escort to the progress of therapeutic tools and real-world useful applications such as predictive and preventive medicine.

Keywords: CTGF, renal fibrosis signaling pathway, system biology, qualitative modeling

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Authors: A. Siva, R. Senthil, R. Banupriya, R. Saravanakumar

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Cold-formed steel sheets are widely used as primary tension reinforcement in composite slabs. It also performs as formwork for concreting and better ceiling surface. The major type of failure occurring in composite slab is shear failure. When the composite slab is flexurally loaded, the longitudinal shear is generated and transferred to the steel sheet concrete interface. When the load increases, the interface slip occurs. The slip failure can be resisted by mechanical interface interlock by shear studs. In this paper, the slip failure has been resisted by shear connectors and geometry of the steel sheet alone. The geometry of the sheet is kept constant for all the specimens and the type of shear connectors has been varied. Totally, three types of shear connectors (viz., straight headed, U and J) are bolted to the trapezoidal profile sheet and the concrete is casted over it. After curing, the composite slab is subjected to flexure load and the test results are compared with the numerical results analysed by ABAQUS software. The test result shows that the U-shaped bolted stud has higher flexure strength than the other two types of shear connectors.

Keywords: cold formed steel sheet, headed studs, mechanical interlock, shear connectors, shear failure, slip failure

Procedia PDF Downloads 531

Authors: Merrick Lopez, Aashish Abraham, Melissa Egge, Marissa Hood, Jui Shah

Abstract:

A 3 year old male with unknown medical history presented initially with encephalopathy, intubated for respiratory failure, and admitted to the pediatric intensive care unit (PICU) with refractory shock. During resuscitation in the emergency department, he was found to be in severe metabolic acidosis with a pH of 7.03 and escalated on vasopressor drips for hypotension. His initial sodium was 174. He was noted to have burn injuries to his scalp, forehead, right axilla, bilateral arm creases and lower legs. He had rhabdomyolysis (initial creatinine kinase 5,430 U/L with peak levels of 62,340 normal <335 U/L), cardiac injury (initial troponin 88 ng/L with peak at 145 ng/L, normal <15ng/L), hypernatremia (peak 174, normal 140), hypocalcemia, liver injury, acute kidney injury, and neuronal loss on magnetic resonance imaging (MRI). Soft restraints and a shock collar were found in the home. He was critically ill for 8 days, but was gradually weaned off drips, extubated, and started on feeds. Discussion Electrical injury, specifically lightning injury is an uncommon but devastating cause of injury in pediatric patients. This patient with suspected abusive use of a dog shock collar presented similar to a lightning strike. Common entrance points include the hands and head, similar to our patient with linear wounds on his forehead. When current enters, it passes through tissues with the least resistance. Nerves, blood vessels, and muscles, have high fluid and electrolyte content and are commonly affected. Exit points are extremities: our child who had circumferential burns around his arm creases and ankles. Linear burns preferentially follow areas of high sweat concentration, and are thought to be due to vaporization of water on the skin’s surface. The most common cause of death from a lightning strike is due to cardiopulmonary arrest. The massive depolarization of the myocardium can result in arrhythmias and myocardial necrosis. The patient presented in cardiogenic shock with evident cardiac damage. Electricity going through vessels can lead to vaporization of intravascular water. This can explain his severe hypernatremia. He also sustained other internal organ injuries (adrenal glands, pancreas, liver, and kidney). Electrical discharge also leads to direct skeletal muscle injury in addition to prolonged muscular spasm. Rhabdomyolysis, the acute damage of muscle, leads to release of potentially toxic components into the circulation which could lead to acute renal failure. The patient had severe rhabdomyolysis and renal injury. Early hypocalcemia has been consistently demonstrated in patients with rhabdomyolysis. This was present in the patient and led to increased vasopressor needs. Central nervous system injuries are also common which can include encephalopathy, hypoxic injury, and cerebral infarction. The patient had evidence of brain injury as seen on MRI. Conclusion Electrical injuries due to lightning strikes and abusive use of a dog shock collar are rare, but can both present in similar ways with respiratory failure, shock, hypernatremia, rhabdomyolysis, brain injury, and multiorgan damage. Although rare, it is essential for early identification and prompt management for acute and chronic complications in these children.

Keywords: cardiogenic shock, dog shock collar, lightning strike, rhabdomyolysis

Procedia PDF Downloads 63

Authors: Rafael A. B. De Medeiros, Zilmar M. P. Barros, Carlos B. O. De Carvalho, Eunice G. Fraga Neta, Maria I. S. Maciel, Patricia M. Azoubel

Abstract:

The use of the sugar substitution technique (D3S) in mango was studied. It consisted of two stages and the use of ultrasound in one or both stages was evaluated in terms of water loss and solid gain. Higher water loss results were found subjecting the fruit samples to ultrasound in the first stage followed by immersion of the samples in Stevia-based solution with application of ultrasound in the second stage, while higher solids gain were obtained without application of ultrasound in second stage. Samples were evaluated in terms of total carotenoids content and total color difference. Samples submitted to ultrasound in both D3S stages presented higher carotenoid retention compared to samples sonicated only in the first stage. Color of man goes after the D3S process showed notable changes.

Keywords: Mangifera indica L., quality, Stevia rebaudiana, ultrasound

Procedia PDF Downloads 374

Authors: D. De-León-Escobedo, D. J. Delgado-Hernández, S. Pérez

Abstract:

A probabilistic formulation to assess the slopes safety under the hazard of strong storms is presented and illustrated through a slope in Mexico. The formulation is based on the classical safety factor (SF) used in practice to appraise the slope stability, but it is introduced the treatment of uncertainties, and the slope failure probability is calculated as the probability that SF<1. As the main hazard is the rainfall on the area, statistics of rainfall intensity and duration are considered and modeled with an exponential distribution. The expected life-cycle cost is assessed by considering a monetary value on the slope failure consequences. Alternative mitigation measures are simulated, and the formulation is used to get the measures driving to the optimal one (minimum life-cycle costs). For the example, the optimal mitigation measure is the reduction on the slope inclination angle.

Keywords: expected life-cycle cost, failure probability, slopes failure, storms

Procedia PDF Downloads 132

Authors: Ali Hassan, Mian Muhammad Awais, Muhammad Rafique Shahid, Farazia Hassan, Shumaila Rasool

Abstract:

Dusky cotton bug (Oxycarenus laetus) has attained the status of major insect pest of cotton. It is also known as seed bug due to its property of feeding on seeds. It causes floral abscission at flowering stage and reduction in seed germination. Present study was carried out to assess germination loss caused by dusky bug with respect to crop stage and insect intensity. Treatments consisted of three stages immature boll, mature boll and opened boll as well three levels of dusky bug i.e., 50 bugs per boll, 40 bugs per boll along with zero level kept as control. Results showed that the germination percentage was highest in control treatment where no insect was released followed by treatment where 40 insects released and minimum germination showed by treatment in which 50 insects were released. The germination percentage of seeds surpassed after control treatment in the treatment where dusky bugs exposure was given at boll opening stage than on mature boll stage. Minimum germination was observed in immature boll stage. Interaction between crop stages and dusky bug levels showed that germination percentage of seeds was maximum in control treatment then boll opening stage followed by mature boll stage. Minimum seed germination was recorded in dusky bug treatment at immature boll stage which was 34% where 50 insects were released. From the results it is clear that dusky bug should be managed properly at all reproductive stages but immature stage is most critical.

Keywords: Gossypium hirsutum, Oxycarenus laetus, seed bug, seed germination

Procedia PDF Downloads 293

Authors: Md Fazle Alam, Amaj Ahmed Laskar, Hina Younus

Abstract:

Melamine toxicity which causes renal failure and death of humans and animals have recently attracted worldwide attention. Developing an easy, fast and sensitive method for the routine melamine detection is the need of the hour. Herein, we have developed a rapid, sensitive, one step and selective colorimetric method for the detection of melamine in milk samples based upon in-situ formation of silver nanoparticles (AgNPs) via tannic acid at room temperature. These AgNPs thus formed were characterized by UV-VIS spectrophotometer, transmission electron microscope (TEM), zetasizer and dynamic light scattering (DLS). Under optimal conditions, melamine could be selectively detected within the concentration range of 0.05-1.4 µM with a limit of detection (LOD) of 10.1 nM, which is lower than the strictest melamine safety requirement of 1 ppm. This assay does not utilize organic cosolvents, enzymatic reactions, light sensitive dye molecules and sophisticated instrumentation, thereby overcoming some of the limitations of conventional methods.

Keywords: milk adulteration, melamine, silver nanoparticles, tannic acid

Procedia PDF Downloads 231

Authors: Min-Tsai Lai, Taqwa Hariguna

Abstract:

This paper presents a periodical replacement model for a system, considering the concept of single and cumulative repair cost limits simultaneously. The failures are divided into two types. Minor failure can be corrected by minimal repair and serious failure makes the system breakdown completely. When a minor failure occurs, if the repair cost is less than a single repair cost limit L1 and the accumulated repair cost is less than a cumulative repair cost limit L2, then minimal repair is executed, otherwise, the system is preventively replaced. The system is also replaced at time T or at serious failure. The optimal period T minimizing the long-run expected cost per unit time is verified to be finite and unique under some specific conditions.

Keywords: repair-cost limit, cumulative repair-cost limit, minimal repair, periodical replacement policy

Procedia PDF Downloads 338

Authors: Ali Abd El-Aty, Ahmed Tauseef, Ahmad Farooq

Abstract:

This research aims at analyzing and optimizing the hydroforming process parameters to achieve a sound bulged tube without failure. Theoretical constitutive model is formulated to develop a working diagram including process window, which represents the optimize region to carry out the hydroforming process and predict the type of tube failure during the process accurately. The model is applied into different bulging ratios for low carbon steel (C1010). From this study, it is concluded that the tubes with bulging ratios up to 50% and 70% are successfully formed without defects. The tubes with bulging ratio of 90% are successfully formed by hydroforming with optimized the loading path (axial feed versus internal pressure) within the process window. The working diagram is modified due to different types of formation of wrinkling during the hydroforming process. The formation of wrinkles with increasing axial feed can be useful in terms of the achievement of higher bulging ratio and/or less thinning and this type of wrinkles can be overcome through the internal pressure in the later stage of the hydroforming process. On the other hand, the formation of wrinkles may be harmful, if it cannot be reversed.

Keywords: finite element, hydroforming, process window, wrinkling

Procedia PDF Downloads 257

Authors: Wang Liguang, Zhang Xueqing

Abstract:

The build-operate-transfer (BOT) project delivery system has provided effective routes to mobilize private sector funds, innovative technologies, management skills and operational efficiencies for public infrastructure development and have been widely used in China during the last 20 years. Many BOT projects in China will be smoothly transferred to the government soon and the transfer stage, which is considered as the last stage, must be studied carefully and handled well to achieve the overall success of BOT projects. There will be many issues faced by both the public sector and private sector in the transfer stage of BOT projects, including project post-assessment, technology and documents transfer, personal training and staff transition, etc. and sometimes additional legislation is needed for future operation and management of facilities. However, most previous studies focused on the bidding, financing, and building and operation stages instead of transfer stage. This research identifies nine key issues in the transfer stage of BOT projects through a comprehensive study on three cases in China, and the expert interview and expert discussion meetings are held to validate the key issues and give detail analysis. A proposed framework of transfer management is prepared based on the experiences derived and lessons drawn from the case studies and expert interview and discussions, which is expected to improve the transfer management of BOT projects in practice.

Keywords: BOT project, key issues, transfer management, transfer stage

Procedia PDF Downloads 224