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Underwater acoustic detection sensors are mounted on the outside of the submarine; the acoustic window for protecting these sensors must be structurally robust while also minimizing any deterioration of sensor's sound detection performance. These two conditions are typically satisfied simultaneously by using composite materials with acoustic window materials. However, since such composite material is manufactured by laminating fibers, there is the probability that delamination occurs, in which an air layer is formed inside, due to manufacturing process errors. Delamination inside the acoustic window degrades the sensor's acoustic performance and results in a failure of military operations. In the case of composites composed of sandwich structures located in the central part, the possibility of internal delamination is higher than in a single composite material. Therefore, it is very important to discriminate the presence or absence of internal delamination after producing an acoustic window. This article uses numerical and analytical methods to determine the internal delamination of the acoustic window fabricated with a sandwich structure. In addition, the results were analyzed and compared through ultrasonic measurement and acoustic transmission loss test. [ABSTRACT FROM AUTHOR]

This study investigates the diagnostic value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with 109 classical fever of unknown origin (FUO). Of the 48 18F-FDG PET/CT scans, 41 (85.4%) were interpreted as abnormal, and 25 (52.1% of all scans) were considered clinically helpful. The final cause of fever was determined in 41 patients (85.4%); infection (25%), malignancy (12.5%), non-infectious inflammatory disease (16.7%) and miscellaneous causes (31.3%). 18F-FDG PET/CT contributed to the final diagnosis of FUO in 65.8%. [ABSTRACT FROM AUTHOR]

Background: Infectious complications are major factors for morbidity and mortality in liver transplant recipients. To establish a proper strategy to reduce infectious complications, we analyzed epidemiologic and risk factors for post-transplant infections., Methods: We analyzed the medical records of 231 consecutive liver transplant recipients from December 2007 to November 2011, including at least 1-year follow up, for comparison with those from 1996 to 2005., Results: Among 231 patients, 126 (54.5%) experienced 244 infectious episodes, a rate of 1.05 per patient. Among overall mortality of 9.9% (23/231), infections were more prevalent (P = .04). Predominant infections were postoperative intra-abdominal problems (36.1%), peritonitis (15.2%), pneumonia (13.5%), bacteremia (4.1%), wound complications (1.6%), viral etiologies (18.0%), and other causes (11.5%). Causative organisms were bacterial (68.9%), viral (14.7%), fungal (7.0%), and unproven ones (9.4%). Multivariate analysis of risks for infection showed significant impacts of Model for End-stage Liver Disease score [P = .027; odds ratio (OR), 1.04], post-transplant biliary complications (P < .001; OR, 3.50), and rejection episodes (P = .023; OR, 3.39). Mortality was related to retransplantation (P = .003), post-transplant dialysis (P = .006), and infection (P = .056) upon univariate analysis, none of which were significant in multivariate analysis. Compared with data from the previous period, overall and infection-related mortality decreased from 24.5% to 9.9% and 52.9% to 26.1%, respectively. There were no significant changes in the types of infection or rate of drug-resistant bacteria, but candidal infections and cytomegalovirus reactivations were more prevalent., Conclusion: Our data showed current perioperative antimicrobial regimens need not be changed: however, new strategies are needed to reduce infectious complications after liver transplantation, to reduce biliary complications and to properly manage rejection episodes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: Cytomegalovirus (CMV), the most significant viral infection in liver transplant recipients, is addressed by 2 methods: Preemptive therapy (PT) or universal prophylaxis (UP)., Methods: We analyzed medical records including at least 1 year follow-up of patients who underwent liver transplantation from 2006 to 2009 in 3 tertiary hospitals. PT was used in 2 hospitals (PT group), whereas UP with valganciclovir for 3 months was adopted in the other hospital (UP group). The 2 groups were matched using propensity scoring by perioperative variables. We performed a 1:1 comparison of the efficacy of UP and PT., Results: We analyzed 634 liver transplant patients, including 562 matched subjects. Baseline characteristics and underlying liver status were comparable. CMV immunoglobulin G of recipients was positive in 98.9% of the PT group and 99.3% of the UP group. CMV viremia episodes that required administration of an antiviral agent occurred in 26 (9.3%) PT and 37 (13.2%) UP subjects (P = .18). CMV-related mortalities were similar (0.7% vs 1.8%; P = .45), but all-cause mortality was higher in the PT group (18.5% vs 13.2%; P = .08)., Conclusion: The efficacy of PT was similar to UP to prevent CMV disease and related mortality among a group at moderate risk for CMV infection., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Acinetobacter species have become increasingly important nosocomial pathogens worldwide and can result in a wide range of infections, including bacteremia, pneumonia, urinary tract infection, peritonitis, among others. The aim of this study was to investigate clinical characteristics, mortality, and outcomes among liver transplant recipients with Acinetobacter species infections., Methods: We retrospectively analyzed 451 subjects who had undergone living donor liver transplantations between January 2001 and May 2010. Pandrug-resistant (PDR) Acinetobacter species were defined as resistant to all commercially available antibiotics except colistin., Results: Infectious complications due to Acinetobacter species appeared in 26 patients (5.8%) with a total of 37 episodes. Of the species identified, 34 were Acinetobacter baumannii and 3 Acinetobacter Iwoffiii. The presumed sources of infection were the biliary tract (n = 21, 56.8%), lung (n = 7, 18.9%), intra-abdomen (n = 6, 16.2%), catheter (n = 2, 5.4%), and urinary tract (n = 1, 3.6%). Among the 37 Acinetobacter species, 75.7% (28/37) were PDR species. Age, duration of intensive care unit stay, Child-Pugh score, and Model for End-stage Liver Disease score were not significant risk factors for Acinetobacter species infection. However, the overall mortality among patients with Acinetobacter species infections was 50% (13/26), which was significantly higher than that among those free of infection (50% vs 11.5%, P < .05). Multivariate analysis using a Cox regression model showed that inappropriate antimicrobial treatment was a significant independent risk factor for mortality among patients with Acinetobacter species infections (hazard Ratio = 4.19, 95% confidence interval 1.1-18.7; P = .06)., Conclusion: Patients with Acinetobacter species infections after liver transplantation show a significantly worse prognosis. PDR Acinetobacter species have been a major problem in our center., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: The goals of a surveillance for nosocomial infections (NIs) are to observe the magnitude and characteristics of NIs and to plan and evaluate policies and guidelines of infection control. This study was designed to determine the rate and distribution of NIs and their causative pathogens in Korean hospitals., Methods: Prospective surveillance was performed at 15 acute care hospitals with more than 500 beds during a 3-month period from June to August 1996. The case-finding methods were laboratory-based surveillance for patients in the general wards and a direct review of medical charts done regularly for all the patients in the intensive care units., Results: A total of 3162 NIs were found among 85,547 discharged patients, with an overall nosocomial infection rate of 3.70 per 100 patients discharged. Urinary tract infections constituted 30.3% of all NIs. Other infections were pneumonias, 17.2%, surgical site infections, 15.5%, and primary bloodstream infections, 14.5%. The infection rate was the highest in neurosurgery (14.21), followed by neurology (8. 62) and ontology services (6.70). The infection rate in intensive care units was higher than it was in the general wards (10.74 vs 2. 57, P =.001). The commonly isolated organisms were Staphylococcus aureus (17.2%), Pseudomonas aeruginosa (13.8%), and Escherichia coli (12.3%)., Conclusions: This first multicenter surveillance study provided extensive information on the current status and trends of NIs in major hospitals in Korea. The results may contribute to the evaluation of infection control programs and the development of effective strategies in these hospitals.

We applied infrequent-restriction-site PCR (IRS-PCR) to the investigation of an outbreak caused by 23 isolates of Acinetobacter baumannii in an intensive care unit from November 1996 to May 1997 and a pseudoepidemic caused by 16 isolates of Serratia marcescens in a delivery room from May to September 1996. In the epidemiologic investigation of the outbreak caused by A. baumannii, environmental sampling and screening of all health care workers revealed the same species from the Y piece of a mechanical ventilator and the hands of two health care personnel. IRS-PCR showed that all outbreak-related strains were genotypically identical and that three strains from surveillance cultures were also identical to the outbreak-related strains. In a pseudoepidemic caused by S. marcescens, IRS-PCR identified two different genotypes, and among them one genotype was predominant (15 of 16 [93.8%] isolates). Extensive surveillance failed to find any source of S. marcescens. Validation of the result of IRS-PCR by comparison with that of field inversion gel electrophoresis (FIGE) showed that they were completely concordant. These results suggest that IRS-PCR is comparable to FIGE for molecular epidemiologic studies. In addition, IRS-PCR was less laborious and less time-consuming than FIGE. To our knowledge, this is the first report of the application of IRS-PCR to A. baumannii and S. marcescens.

We analyzed an outbreak of Escherichia coli bacteremia in eight patients with leukemia in a hematology-oncology unit from July to September 1994. The antibiograms and genotypic patterns of the isolates were different, thus suggesting that the outbreak did not originate from a single clone. However, all the isolates were resistant to quinolones, which led us to examine the microbiological records from 1992 to 1994. The incidence of quinolone-resistant E. coli bacteremia in the hematology-oncology unit ranged from 81.8% to 94.6% during this period. We then analyzed 36 more isolates recovered from late 1994 to 1995. Field inversion gel electrophoresis patterns of these isolates were also different. Analysis of the quinolone resistance determining region in gyrA revealed that all the isolates had a double mutation in gyrA. In conclusion, quinolone-resistant E. coli could be an emerging threat to neutropenic patients with leukemia who receive a quinolone prophylactically, and attention must be paid to this trend of resistance.

Two outbreaks of acute toxoplasmosis involving 8 adult patients in Korea were linked to eating uncooked pork. In the first outbreak, 3 patients developed unilateral chorioretinitis within 3 months of eating a meal consisting of raw spleen and liver of a wild pig. In the second outbreak, 5 of 11 soldiers who ate a meal consisting of raw liver of a domestic pig developed lymphadenopathy. All 8 patients had high levels of IgG Toxoplasma gondii antibodies (> or = 1:1024) in the Sabin-Feldman dye test, modified agglutination test incorporating mercaptoethanol, and latex agglutination test. T. gondii IgM antibodies persisted in these patients for several months. Most patients had a favorable response to anti-T. gondii chemotherapy with pyrimethamine and sulfanomides.

Epstein-Barr virus (EBV)-associated gastric carcinomas have been reported from various regions of the world. Epstein-Barr virus appears to be pathogenetically related to some gastric carcinomas. To determine the incidence of EBV association with gastric carcinomas among Koreans, the authors have studied EBV genome expression in 89 consecutive patients with gastric carcinomas diagnosed at the Catholic University Hospitals in Seoul, Korea, using in situ hybridization (ISH) for EBV-encoded small RNAs (EBERs), and immunohistochemistry for EBV latent membrane proteins (LMP) and CD21 antigen on paraffin sections. Thirty-seven gastric specimens with benign ulcer disease were used controls. EBV-encoded small RNAs were expressed in tumor cell nuclei in 12 patients (13.5%). None of the controls or benign portions of the cases were positive. In the positive cases, all tumor cell nuclei were uniformly stained and the staining intensity was strong. Immunohistochemistry for LMP was positive in 3 of 12 EBERs positive patients and none of EBERs negative patients. EBV latent membrane proteins was localized only in the lymphoid cells infiltrating the tumor in two patients, and tumor cells as well as infiltrating lymphoid cells in one patient. These results indicate that the rate of EBV association with gastric carcinomas in Koreans is relatively high and comparable to other Far Eastern Asian regions. The expression pattern in EBV-associated gastric carcinomas is similar to those of nasopharyngeal carcinomas in which clonality analysis using specific probes to the tandem repeat region of EBV yielded single episomal bands suggesting that EBV infection in EBV-associated gastric carcinomas are also clonal and pathogenetically related to the neoplasm. However, the mechanism of tumorigenesis remains to be elucidated.

The immunogenicity of a single dose of Salmonella typhi(S.typhi) Vi capsular polysaccharide(CPS) vaccine was evaluated before, and at 1, 3, 12, and 36 months after vaccination. Eighty-five adults(20-28 years of age) and sixty-four children(8-16 years of age) received a single dose of 25 micrograms Vi CPS vaccine intramuscularly, and antibody titers to Vi CPS were measured by passive hemagglutination. Of 149 vaccinees, 138(92.6%) showed seroconversion at 1 month after vaccination, and then 138 out of 141(97.9%) did at 3 months. Of 137 vaccinees, 116(84.7%) maintained a persistent rise in Vi antibody titer 12 months after vaccination, and 55 out of 100(55.0%) had a 4-fold or greater rise at 36 months. No significant adverse reactions were observed. Booster injection may be needed 3-5 years after vaccination.

Expression of proliferating cell nuclear antigen (PCNA) and numbers of nucleolar organizer regions (NORs) were studied by immunohistochemistry and the silver staining technique in 99 meningiomas and related to histopathologic grading, recurrence and their predictive value for recurrence. The results indicated that there was a significant correlation between PCNA or AgNORs and histopathologic grading of meningiomas. Slightly higher expression of PCNA in atypical meningiomas was correlated with the increased recurrence rate; however, expression of PCNA and numbers of AgNORs in meningiomas are not reliable criteria to predict tumor recurrence.