• Childhood Kidney Diseases
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• v.19 no.2
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• pp.143-147
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• 2015

Purpose: Burkholderia cepacia is an aerobic, glucose-non-fermenting, gram-negative bacillus that mainly affects immunocompromised and hospitalized patients. Burkholderia cepacia has high levels of resistance to many antimicrobial agents, and therapeutic options are limited. The authors sought to analyze the incidence, clinical manifestation, risk factors, antimicrobial sensitivity and outcomes of B. cepacia urinary tract infection (UTI) in pediatric patients. Methods: Pediatric patients with urine culture-proven B. cepacia UTI between January 2000 and December 2014 at Samsung Medical Center, a tertiary referral hospital in Seoul, Republic of Korea, were included in a retrospective analysis of medical records. Results: Over 14 years, 14 patients (male-to-female ratio of 1:1) were diagnosed with B. cepacia UTI. Of 14 patients with UTI, 11 patients were admitted to the intensive care unit, and a bladder catheter was present in 9 patients when urine culture was positive for B. cepacia. Patients had multiple predisposing factors for UTI, including double-J catheter insertion (14.2%), vesico-ureteral reflux (28.6%), congenital heart disease (28.6%), or malignancy (21.4%). Burkholderia cepacia isolates were sensitive to piperacillin-tazobactam and sulfamethoxazole-trimethoprim, and resistant to amikacin and colistin. Treatment with parenteral or oral antimicrobial agents including piperacillin-tazobactam, ceftazidime, meropenem, and sulfamethoxazole-trimethoprim resulted in complete recovery from UTI. Conclusion: Burkholderia cepacia may be a causative pathogen for nosocomial UTI in pediatric patients with predisposing factors, and appropriate selection of antimicrobial therapy is necessary because of high levels of resistance to empirical therapy, including aminoglycosides.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.307-313
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• 2014

In this study, an optimization process design has been performed to separate 99.9 mol% of Isobutyl Acetate from binary azeotropic mixture of Isobutyl Acetate and Isobutyl Alcohol system using a Pressure Swing Distillation (PSD). PSD is used to separate binary azeotropic mixtures using the difference between the relative volatilities and azeotropic compositions by changing the system pressure. Non-Random Two Liquid (NRTL) model for liquid phase and the Peng-Robinson equation for vapor phase are used. An optimization study for the reflux ratio and feed stage locations which minimize the total reboiler heat duties are studied. Since PSD process consists of two columns, i.e. high pressure and low pressure, the effect of column sequence on the optimum conditions is reported.

• Advanced Composite Materials
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• v.18 no.2
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• pp.187-195
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• 2009

Much attention has been paid to the processing of inorganic whisker, especially calcium carbonate whisker, which can be used as reinforcement materials of polymer composite due to its low price. Unfortunately, the present synthesis technique of calcium carbonate whisker starts from calcinations of limestone, which involves high energy consumption and furthermore is a highly environment polluting reaction. In this report, needle-like aragonite was synthesized with a reversible solution reaction from limestone without calcination. Optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to characterize the morphology and crystal structure of intermediates as well as that of the product, aragonite. GCC (grinding calcium carbonate) powder was dissolved in an aqueous solution of magnesium sulfate with reflux and air flush. EDTA titration was used to evaluate reaction rate of the dissolution. A kinetics equation of the dissolution reaction was constructed, which displayed second-order kinetics with respect to the concentration of magnesium sulfate. A rate constant of $0.0015\;l^{-3}{\cdot}mol^{-1}{\cdot}h^{-1}$ was obtained. The dissolution reaction gave fiber-like magnesium hydroxide sulfate and gypsum crystal. Then needle-like aragonite with a length of $9.13\;{\pm}\;1.02\;{\mu}m$ and an aspect ratio of $5.64\;{\pm}\;1.37$ was synthesized from the dissolution product with $CO_2$ bubbling at $70^{\circ}C$.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.279-286
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• 2020

In this article, we develop a reactive distillation (RD) column configuration for the production of hydrogen. This RD column is in the HI decomposition section of the sulphur - iodine (SI) thermochemical cycle, in which HI decomposition and H₂ separation take place simultaneously. The section plays a major role in high hydrogen production efficiency (that depends on reaction conversion and separation efficiency) of the SI cycle. In the column simulation, the rigorous thermodynamic phase equilibrium and reaction kinetic model are used. The tuning parameters involved in phase equilibrium model are dependent on interactive components and system temperature. For kinetic model, parameter values are adopted from the Aspen flowsheet simulator. Interestingly, there is no side reaction (e.g., solvation reaction, electrolyte decomposition and polyiodide formation) considered aiming to make the proposed model simple that leads to a challenging prediction. The process parameters are determined on the basis of optimal hydrogen production as reflux ratio = 0.87, total number of stages = 19 and feeding point at 8th stage. With this, the column operates at a reasonably low pressure (i.e., 8 bar) and produces hydrogen in the distillate with a desired composition (H₂ = 9.18 mol%, H₂O = 88.27 mol% and HI = 2.54 mol%). Finally, the results are compared with other model simulations. It is observed that the proposed scheme leads to consume a reasonably low energy requirement of 327 MJ/kmol of H₂.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5741-5747
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• 2015

Purpose: To understand the epidemiology of different upper gastrointestinal (UGI) tract related abnormalities through endoscopic data analysis. Materials and Methods: A retrospective study of three years from January 2009 to December 2011 was conducted with data from endoscopic surveillance of upper GI tract problems, collected from the Gastroenterology Unit, Osmania General Hospital, Hyderabad. MS excel and Medcalc software (comparison of proportions) were used for data analysis. Results: A total of 10,029 (6,468 in males and 3,561 in females) endoscopies were performed during this three-year period. The male to female ratio was 1.8:1. Overall, ~30% of endoscopies evaluated showed patients with acid peptic disorders, 13.6% with vascular-related abnormalities, 10.6% showed structural abnormalities, followed by 6.3% with malignancies. Burden of malignancies was mostly observed in the older age group (60-69 years). Esophageal cancer cases decreased (p=0.0001) whereas stomach cancers increased over this period (p=0.0345). We also observed an increased incidence of acid peptic disease (APD) (p=0.0036) and gastroesophageal reflux disease (GERD) (p=0.0002) cases during this period. Conclusions: Endoscopic diagnosis is useful for early detection of UGI anomalies and helpful for physicians to manage and treat varied kinds of UGI disorders. Analysis of data revealed changing trends in the incidence of various pathologies of the UGI tract. Functional dyspepsia and GERD definitely reduce the quality of life of the individual. The role of our diverse dietary habits and lifestyle associated with these problems have not yet been established, though there have been reports on the effect of coffee, spicy food, wheat-based diet, screening of UGI pathologies along with collection of complete personal and medical history details, can h elp in correlating the patients' condition with various aspects of lifestyle and diet.

• Clinical and Experimental Pediatrics
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• v.64 no.6
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• pp.293-300
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• 2021

Background: Understanding the epidemiology and prevalence of febrile urinary tract infection (fUTI) in children is important for risk stratification and selecting appropriate urine sample collection candidates to aid in its diagnosis and treatment. Purpose: This study aimed to analyze the epidemiology, etiology, and changes in antibiotic susceptibility patterns of the first fUTI in children. Methods: This retrospective observational cohort study included children younger than 19 years of age who were diagnosed and treated for their first fUTI in 2006-2016. Electronic medical records were analyzed and radiologic images were evaluated. Results: A total of 359 patients (median age, 5.1 months; interquartile range, 3.0-10.5 months) fit the inclusion criteria; of them, 78.0% (n=280) were younger than 12 months old. The male to female ratio was 5.3:1 for patients aged 0-2 months, 2.1:1 for those 3-5 months, and 1.6:1 for those 6-11 months. Beyond 12 months of age, there was a female predominance. Escherichia coli was the leading cause (83.8%), followed by Enterococcus species (6.7%), and Klebsiella pneumoniae (3.6%). Significant yearly increases in the proportions of multidrug-resistant strains (P<0.001) and extended-spectrum beta-lactamase (ESBL) producers (P<0.001) were observed. In patients with vesicoureteral reflux (VUR), the overall recurrence rate was 53.6% (n=15). A significantly higher recurrence rate was observed when the fUTI was caused by an ESBL versus non-ESBL producer (75.0% vs. 30.0%, P=0.03). Conclusion: fUTI was most prevalent in children younger than 12 months of age and showed a female predominance in patients older than 12 months of age. The proportion of ESBL producers causing fUTI is increasing. Carbapenems, rather than noncarbapenems, should be considered for treating fUTI caused by ESBL-producing enteric gram-negative rods to reduce short-term recurrence rates in children with VUR.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.32 no.1
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• pp.24-28
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• 2021

Background and Objectives Vocal polyp is one of the most common benign diseases of vocal fold caused by overuse of voice. Laryngeal microsurgery is the first treatment of choice for vocal polyp. However, surgery has many risks such as side effects of general anesthesia, injury of tooth and psychological burden. And we often experience reduction of vocal polyps without surgical procedure. The purpose of study is to evaluate the effect of non-surgical treatment such as vocal hygiene education and proton pump inhibitor (PPI) in patients with vocal polyp. Materials and Method We performed retrospective study for seventy-three patients of vocal polyp who treated with non-surgical modalities such as vocal hygiene education and PPI over three months. Treatment outcomes and risk factors such as age, sex, polyp size, position, symptom duration, presence of laryngopharyngeal reflux (LPR) symptoms, smoking history, voice abuse history and vocal hygiene education were evaluated by comparison between polyp size improved group and non-improved group. Results 5.5% of enrolled patients showed complete response and 23.3% showed partial response without surgery. Polyp size improved group significantly carried out more practice of vocal hygiene education treatment than the non-improved group (p=0.040). And the presence of LPR symptoms [hazard ratio (HR) 3.368, confidence interval (CI) 1.055-10.754, p=0.040] and not performing of vocal hygiene education (HR 3.664, 95% CI 1.078-12.468, p=0.038). Conclusion Vocal hygiene education can be a useful treatment option when making a decision to treat with vocal polyp.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.1
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• pp.59-86
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• 2023

Purpose: Information regarding functional gastrointestinal disorders (FGIDs) in infants is currently lacking in Indonesia. This study aimed to describe the prevalence and risk factors of FGIDs in infants aged 6 weeks to 4 months in Indonesia. Methods: This cross-sectional study of 433 infants was conducted between September 2018 and February 2020. Information on FGIDs was collected using the Infant Gastrointestinal Symptom Questionnaire and the Feeding Practice and Gut Comfort Questionnaire. Adapted Rome IV criteria were used to define the FGIDs. Results: The prevalence of regurgitation was 26.3%; 16.8% of the infants presented cryingrelated symptoms and 5.5% exhibited constipation. The statistical analyses revealed that constipation was associated with sex (odds ratio [OR], 2.74; 95% confidence interval [CI], 1.07-7.71; p=0.043), employment of the father (OR, 0.3; 95% CI, 0.12-0.77; p=0.01), and education of the mother (OR, 1.92; 95% CI, 1.07-3.51; p=0.031). Length at birth (OR, 0.74; 95% CI, 0.55-0.99; p=0.042) was associated with constipation. Length at visit (OR, 0.83; 95% CI, 0.76-0.91; p<0.001) was associated with regurgitation, and the weight at visit (OR, 0.58; 95% CI, 0.35-0.96; p=0.038) was associated with crying and/or colic. A history of parental FGIDs was associated with crying-related symptoms (OR, 2.12; 95% CI, 1.23-3.68; p=0.007). Conclusion: Regurgitation, crying, and constipation are common FGIDs in infants. Some parental and infant characteristics may be predictors for FGIDs. Further investigations are needed to evaluate the clinical relevance of our findings. Understanding the determinants of FGIDs will benefit healthcare professionals and parents to improve infant's quality of life and better manage these condition.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.588-596
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• 1996

The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fire reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI's color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4'-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4'-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above $38.4^{\circ}C$. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it's color and conducts self-polymerization reaction. To increase the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.739-746
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• 2008

The aim of this study is finding the optimal design parameters and the optimal operation variables of a reactive distillation column. Different from steady state optimization, dynamic optimization makes it possible considering operation ability as well as design problems at process design step. For performing dynamic optimization, dynamic simulation should be done first. If dynamic simulation is already finished, dynamic optimization can be performed with less effort than that of dynamic simulation.Reactive distillation systems involving reaction and separation in a single unit have the potential to reduce capital and operating costs, particularly when reaction have conversion constraint or when azeotropes exist making conventional separation difficult and expensive. This study here present work on the continuous distillation process, the homogeneous catalyzed esterification of methanol and acetic acid, the synthesis of methyl acetate. Based on an equilibrium stage model of a reactive distillation column a dynamic optimization problem was formulated and solved. And the results were verified by performing dynamic simulation and showing the variation of conversion and purity as the variation of the operation variables. As the results of dynamic optimization, this study found optimal feed ratio, reflux ratio and reboiler duty of this system. And as this study applied it to dynamic simulations the dynamic characteristics of a reactive distillation column are showed under optimal operating condition.