• Title/Summary/Keyword: structural susceptibility

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An update on necrotizing enterocolitis: pathogenesis and preventive strategies

  • Lee, Jang-Hoon
    • Clinical and Experimental Pediatrics
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    • v.54 no.9
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    • pp.368-372
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    • 2011
  • Necrotizing enterocolitis (NEC) is one of the most critical morbidities in preterm infants. The incidence of NEC is 7% in very-low-birthweight infants, and its mortality is 15 to 30%. Infants who survive NEC have various complications, such as nosocomial infection, malnutrition, growth failure, bronchopulmonary dysplasia, retinopathy of prematurity, and neurodevelopmental delays. The most important etiology in the pathogenesis of NEC is structural and immunological intestinal immaturity. In preterm infants with immature gastrointestinal tracts, development of NEC may be associated with a variety of factors, such as colonization with pathogenic bacteria, secondary ischemia, genetic polymorphisms conferring NEC susceptibility, anemia with red blood cell transfusion, and sensitization to cow milk proteins. To date, a variety of preventive strategies has been accepted or attempted in clinical practice with regard to the pathogenesis of NEC. These strategies include the use of breast feeding, various feeding strategies, probiotics, prebiotics, glutamine and arginine, and lactoferrin. There is substantial evidence for the efficacy of breast feeding and the use of probiotics in infants with birth weights above 1,000 g, and these strategies are commonly used in clinical practice. Other preventive strategies, however, require further research to establish their effect on NEC.

Study of exterior beam-column joint with different joint core and anchorage details under reversal loading

  • Rajagopal, S.;Prabavathy, S.
    • Structural Engineering and Mechanics
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    • v.46 no.6
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    • pp.809-825
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    • 2013
  • In the present study, in reinforced concrete structures, beam-column connections are one of the most critical regions in areas with seismic susceptibility. Proper anchorage of reinforcement is vital to enhance the performance of beam-column joints. Congestion of reinforcement and construction difficulties are reported frequently while using conventional reinforcement detailing in beam-column joints of reinforced concrete structures. An effort has been made to study and evaluate the performance of beam-column joints with joint detailing as per ACI-352 (mechanical anchorage), ACI-318 (conventional hooks bent) and IS-456(full anchorage conventional hooks bent) along with confinement as per IS-13920 and without confinement. Apart from finding solutions for these problems, significant improvements in seismic performance, ductility and strength were observed while using mechanical anchorage in combination with X-cross bars for less seismic prone areas and X-cross bar plus hair clip joint reinforcement for higher seismic prone areas. To evaluate the performances of these types of anchorages and joint details, the specimens were assembled into four groups, each group having three specimens have been tested under reversal loading and the results are presented in this paper.

Detection of $\beta$-lactam Antibiotic-resistant Genes in Eschericia coli using DNA Chip from Porcine Fecal Samples

  • Na, Sung-ho;Cho, Ho-seong;Kim, Yong-hwan;A.W.E. Effendy;Park, Nam-yong
    • Proceedings of the Korean Society of Veterinary Pathology Conference
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    • 2003.10a
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    • pp.33-33
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    • 2003
  • There prevalence of $\beta$-lactamases bacteria in animals has been increased since 1990s [1]. The resistance in E coli which is mediated by $\beta$-lactamases hydrolyze the $\beta$-lactam ring eventually inactivate the antibiotics [2]. Generally, $\beta$-lactamases can be classified into four main groups and eight subgroups according to their functional and structural characteristics [3]. The detection of $\beta$-lactam antibiotic-resistant bacteria by DNA chip has been described [4]. The chip has a specific probe DNAs that contained the $\beta$-lactam antibiotic-resistant genes which was labeled by multiplex PCR reaction with a mixture of primer sets that were designed to amplify specific gene. Here we report the susceptibility of enteropathogenic E. coli isolated from pigs in Korea using the DNA chip in detecting $\beta$-lactam antibiotic-resistant genes. (omitted)

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Health Blief Model-based intervention to improve nutritional behavior among elderly women

  • Iranagh, Jamileh Amirzadeh;Rahman, Hejar Abdul;Motalebi, Seyedeh Ameneh
    • Nutrition Research and Practice
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    • v.10 no.3
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    • pp.352-358
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    • 2016
  • BACKGROUND/OBJECTIVES: Nutrition is a determinant factor of health in elderly people. Independent living in elderly people can be maintained or enhanced by improvement of nutritional behavior. Hence, the present study was conducted to determine the impact of Health Belief Model (HBM)-based intervention on the nutritional behavior of elderly women. SUBJECTS/METHODS: Cluster-random sampling was used to assess the sample of this clinical trial study. The participants of this study attended a 12-week nutrition education program consisting of two (2) sessions per week. There was also a follow-up for another three (3) months. Smart PLS 3.5 and SPSS 19 were used for structural equation modeling, determination of model fitness, and hypotheses testing. RESULTS: The findings indicate that intervention had a significant effect on knowledge improvement as well as the behavior of elderly women. The model explained 5 to 70% of the variance in nutritional behavior. In addition, nutritional behavior was positively affected by the HBM constructs comprised of perceived susceptibility, self-efficacy, perceived benefits, and barriers after the intervention program. CONCLUSION: The results of this study show that HBM-based educational intervention has a significant effect in improving nutritional knowledge and behavior among elderly women.

Concurrent engineering solution for the design of ship and offshore bracket parts and fabrication process

  • Kim, Tae-Won;Lim, Sang-Sub;Seok, Ho-Hyun;Kang, Chung-Gil
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.3
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    • pp.376-391
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    • 2013
  • Brackets in ships and offshore structures are added structures that can endure stress concentrations. In this study, a concurrent engineering solution was proposed, and a high strength low carbon cast steel alloy applicable to offshore structures was designed and developed. The yield strength and ultimate tensile strength of the designed steel were 480 and 600 MPa, respectively. The carbon equivalent of the steel was 0.446 with a weld crack susceptibility index of 0.219. The optimal structural design of the brackets for offshore structures was evaluated using ANSYS commercial software. The possibility of replacing an assembly of conventional built-up brackets with a single casting bulb bracket was verified. The casting process was simulated using MAGMAsoft commercial software, and a casting fabrication process was designed. For the proposed bulb bracket, it was possible to reduce the size and weight by approximately 30% and 50%, respectively, compared to the conventional type of bracket.

Influence of initial imperfections on ultimate strength of spherical shells

  • Yu, Chang-Li;Chen, Zhan-Tao;Chen, Chao;Chen, Yan-ting
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.9 no.5
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    • pp.473-483
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    • 2017
  • Comprehensive consideration regarding influence mechanisms of initial imperfections on ultimate strength of spherical shells is taken to satisfy requirement of deep-sea structural design. The feasibility of innovative numerical procedure that combines welding simulation and non-linear buckling analysis is verified by a good agreement to experimental and theoretical results. Spherical shells with a series of wall thicknesses to radius ratios are studied. Residual stress and deformations from welding process are investigated separately. Variant influence mechanisms are discovered. Residual stress is demonstrated to be influential to stress field and buckling behavior but not to the ultimate strength. Deformations are proved to have a significant impact on ultimate strength. When central angles are less than critical value, concave magnitudes reduce ultimate strengths linearly. However, deformations with central angles above critical value are of much greater harm. Less imperfection susceptibility is found in spherical shells with larger wall thicknesses to radius ratios.

Structural and Magnetic Properties of the Brownmillerite $Ca_2Al_xFe_{2-x}O_5$ System

  • 김귀야;로권선;여철현
    • Bulletin of the Korean Chemical Society
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    • v.16 no.10
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    • pp.934-938
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    • 1995
  • A series of solid solutions in the Ca2AlxFe2-xO5 (x=0.00, 0.50, 0.66, 1.00 and 1.34) system with brownmillerite structure has been synthesized at 1100 ℃ under an atmospheric air pressure. The solid solutions are analysed by powder x-ray diffraction analysis, Mohr salt titration, thermal analysis, and Mossbauer spectroscopic analysis. The x-ray diffraction analysis assigns the compositions of x=0.00 and 0.50 to the space group Pcmn and those of x=0.66, 1.00, and 1.34 to the Ibm2. Mo&ssbauer spectra have shown the coordination state and disordering of Al3+ and Fe3+ ions. The substituting preference of Al3+ ions for the tetrahedral site decreases with increasing x value. Magnetic susceptibility of the system has been measured in the temperature range of 5 K to 900 K. The solid solutions of the compositions of x=0.00, 0.50 and 0.66 have shown a thermal hysteresis and the thermoremanent magnetization gap decreases with increasing x value in the above systems. However the compositions of x=1.00 and 1.34 do not show the hysteresis. The exchange integral is calculated from Fe3+ ion occupancy ratio. The integral decreases with x value and thus the magnetic transition temperature decreases with the increasing x value.

Substitutional Effects of Na in the YB$a_2Cu_3O_{7-y}$ Oxide Superconductors

  • Hur Nam Hwi;Ha, Dong Han;Park Yong Ki;Park, Jong Chul
    • Bulletin of the Korean Chemical Society
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    • v.13 no.4
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    • pp.425-428
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    • 1992
  • Sodium substituted samples of $Y_{1-x}Na_xBa_2Cu_3O_{7-y}$ for $0.00{\leq}x{\leq}0.16$ were prepared and characterized by X-ray powder pattern, electrical resistivity and magnetic susceptibility measurements, Raman spectroscopy, and idometric titration. The Na substituted compounds have narrow solid solution limits where $0.00{\leq}x{\leq}0.16.$ As the Na concentration increases, the parent orthorhombic structure tends to gradually change to tetragonal. Small changes in the superconducting transition temperature, Tc, are observed in this solid solution region. Raman spectra for the Na phases are virtually identical with that of $YBa_2Cu_3O_7$ except that the Cu(1)-O(4) stretching mode at 504 $cm^{-1}$ and the Cu(2)-O(2,3) bending mode at 340 $cm^{-1}$ for x = 0.16 are slightly shifted. The hole concentrations of the sodium substituted compounds ranged from 0.31 to 0.33 per Cu site are increased with Na content. The substitution of $Na^+$ for $Y^{3+}$ site appears to create oxygen vacancies in the Cu-O chains, causes structural change from orthorhombic to tetragonal, and increases hole concentration in the substituted system.

Modeling flow instability of an Algerian sand with the dilatancy rule in CASM

  • Ramos, Catarina;Fonseca, Antonio Viana da;Vaunat, Jean
    • Geomechanics and Engineering
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    • v.9 no.6
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    • pp.729-742
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    • 2015
  • The aim of the present work was the study of instability in a loose sand from Les Dunes beach in Ain Beninan, Algeria, where the Boumerdes earthquake occurred in 2003. This earthquake caused significant structural damages and claimed the lives of many people. Damages caused to infrastructures were strongly related to phenomena of liquefaction. The study was based on the results of two drained and six undrained triaxial tests over a local sand collected in a region where liquefaction occurred. All the tests hereby analyzed followed compression stress-paths in monotonic conditions and the specimens were isotropically consolidated, since the objective was to study the instability due to static loading as part of a more general project, which also included cyclic studies. The instability was modeled with the second-order work increment criterion. The definition of the instability line for Les Dunes sand and its relation with yield surfaces allowed the identification of the region of potential instability and helped in the evaluation of the susceptibility of soils to liquefy under undrained conditions and its modeling. The dilatancy rate was studied in the points where instability began. Some mixed tests were also simulated, starting with drained conditions and then changing to undrained conditions at different time steps.

EVALUATION OF PRIMARY WATER STRESS CORROSION CRACKING GROWTH RATES BY USING THE EXTENDED FINITE ELEMENT METHOD

  • LEE, SUNG-JUN;CHANG, YOON-SUK
    • Nuclear Engineering and Technology
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    • v.47 no.7
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    • pp.895-906
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    • 2015
  • Background: Mitigation of primary water stress corrosion cracking (PWSCC) is a significant issue in the nuclear industry. Advanced nickel-based alloys with lower susceptibility have been adopted, although they do not seem to be entirely immune from PWSCC during normal operation. With regard to structural integrity assessments of the relevant components, an accurate evaluation of crack growth rate (CGR) is important. Methods: For the present study, the extended finite element method was adopted from among diverse meshless methods because of its advantages in arbitrary crack analysis. A user-subroutine based on the strain rate damage model was developed and incorporated into the crack growth evaluation. Results: The proposed method was verified by using the well-known Alloy 600 material with a reference CGR curve. The analyzed CGR curve of the alternative Alloy 690 material was then newly estimated by applying the proven method over a practical range of stress intensity factors. Conclusion: Reliable CGR curves were obtained without complex environmental facilities or a high degree of experimental effort. The proposed method may be used to assess the PWSCC resistance of nuclear components subjected to high residual stresses such as those resulting from dissimilar metal welding parts.