Analysis of high-contrast all-optical dual-wavelength switching in asymmetric dual-core fibers.

We systematically present experimental and theoretical results for the dual-wavelength switching of 1560 nm, 75 fs signal pulses (SPs) driven by 1030 nm, and 270 fs control pulses (CPs) in a dual-core fiber (DCF). We demonstrate a switching contrast of 31.9 dB, corresponding to a propagation distance of 14 mm, achieved by launching temporally synchronized SP-CP pairs into the fast core of the DCF with moderate inter-core asymmetry. Our analysis employs a system of three coupled propagation equations to identify the compensation of the asymmetry by nonlinearity as the physical mechanism behind the efficient switching performance.

Adopting the Swenson-like technique for patients with Hirschsprung disease in Vietnam.

PURPOSE: To evaluate outcomes of adopting the Swenson-like technique in transanal pull-through for Hirschsprung disease (HD) at a children's institution in Southeast Asia. METHODS: A retrospective chart review was performed over 42 months at a safety-net pediatric hospital in Vietnam. RESULTS: From January 2019 to June 2022, the Swenson-like technique was implemented and performed on 139 patients (115 male, 24 female, mean age 6.4 ± 11.96 months). There were 123 transanal-only resections, 5 transanal plus laparoscopic, and 11 transanal plus laparotomy. The mean operative time was 70.9 ± 43.6 min. The average length of the resected specimen was 18.8 ± 10.9 cm. No urethral or vaginal injuries occurred. Postoperative complications included 1 anastomotic leak (0.7%), 4 anastomotic stenoses (2.8%), and 2 perianal abscesses in the setting of recurrent enterocolitis (1.4%). With a mean follow-up of 26 ± 11.9 months (range 3-48 months), there were 25 enterocolitis cases (17.9%), 45 patients with constipation (32.3%), 1 episode of fecal incontinence lasting longer than 6 months (0.7%), and 1 rectal-vestibular fistula noted one year postoperatively (0.7%). There were no deaths. CONCLUSION: The Swenson-like technique in transanal pull-through for Hirschsprung's disease was safely adopted at our institution. The results show that applying this technique uniformly in a single institution led to excellent outcomes.

Multicenter Study of Device-Associated Infection Rates, Bacterial Resistance, Length of Stay, and Mortality in Intensive Care Units of 2 Cities of Vietnam: International Nosocomial Infection Control Consortium Findings.

OBJECTIVE: The aim of the study was to report the results of the International Nosocomial Infection Control Consortium (INICC) study conducted from May 2008 to March 2015. METHODS: A device-associated healthcare-acquired infection surveillance study in three adult intensive care units (ICUs) and 1 neonatal ICU from 4 hospitals in Vietnam using U.S. the Centers for Disease Control and Prevention's National Healthcare Safety Network (CDC/NHSN) definitions and criteria as well as INICC methods. RESULTS: We followed 1592 adult ICU patients for 12,580 bed-days and 845 neonatal ICU patients for 4907 bed-days. Central line-associated bloodstream infection (CLABSI) per 1000 central line-days rate was 9.8 in medical/surgical UCIs and 1.5 in the medical ICU. Ventilator-associated pneumonia (VAP) rate per 1000 mechanical ventilator-days was 13.4 in medical/surgical ICUs and 23.7 in the medical ICU. Catheter-associated urinary tract infection (CAUTI) rate per 1000 urinary catheter-days was 0.0 in medical/surgical ICUs and 5.3 in the medical ICU. While most device-associated healthcare-acquired infection rates were similar to INICC international rates (4.9 [CLABSI]; 16.5 [VAP]; 5.3 [CAUTI]), they were higher than CDC/NHSN rates (0.8 [CLABSI], 1.1 [VAP], and 1.3 [CAUTI]) for medical/surgical ICUs, with the exception of CAUTI rate for medical/surgical ICU and CLABSI rate for the medical ICU. Because of limited resources of our Vietnamese ICUs, cultures could not be taken as required by the CDC/NHSN criteria, and therefore, there was underreporting of CLABSI and CAUTI, influencing their rates. Most device utilization ratios and bacterial resistance percentages were higher than INICC and CDC/NHSN rates. CONCLUSIONS: Device-associated healthcare-acquired infection rates found in the ICUs of our study were higher than CDC/NHSN US rates, but similar to INICC international rates. It is necessary to build more capacity to conduct surveillance and prevention strategies.

Single and double linear and nonlinear flatband chains: Spectra and modes.

We report results of systematic analysis of various modes in the flatband lattice, based on the diamond-chain model with the on-site cubic nonlinearity, and its double version with the linear on-site mixing between the two lattice fields. In the single-chain system, a full analysis is presented, first, for the single nonlinear cell, making it possible to find all stationary states, viz., antisymmetric, symmetric, and asymmetric ones, including an exactly investigated symmetry-breaking bifurcation of the subcritical type. In the nonlinear infinite single-component chain, compact localized states (CLSs) are found in an exact form too, as an extension of known compact eigenstates of the linear diamond chain. Their stability is studied by means of analytical and numerical methods, revealing a nontrivial stability boundary. In addition to the CLSs, various species of extended states and exponentially localized lattice solitons of symmetric and asymmetric types are also studied, by means of numerical calculations and variational approximation. As a result, existence and stability areas are identified for these modes. Finally, the linear version of the double diamond chain is solved in an exact form, producing two split flatbands in the system's spectrum.

Emergence and Spread of Epidemic Multidrug-Resistant Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) is one of the most common nosocomial pathogens worldwide. Although the emergence of multidrug-resistant (MDR) P. aeruginosa is a critical problem in medical practice, the key features involved in the emergence and spread of MDR P. aeruginosa remain unknown. This study utilized whole genome sequence (WGS) analyses to define the population structure of 185 P. aeruginosa clinical isolates from several countries. Of these 185 isolates, 136 were categorized into sequence type (ST) 235, one of the most common types worldwide. Phylogenetic analysis showed that these isolates fell within seven subclades. Each subclade harbors characteristic drug resistance genes and a characteristic genetic background confined to a geographic location, suggesting that clonal expansion following antibiotic exposure is the driving force in generating the population structure of MDR P. aeruginosa. WGS analyses also showed that the substitution rate was markedly higher in ST235 MDR P. aeruginosa than in other strains. Notably, almost all ST235 isolates harbor the specific type IV secretion system and very few or none harbor the CRISPR/CAS system. These findings may help explain the mechanism underlying the emergence and spread of ST235 P. aeruginosa as the predominant MDR lineage.

Surgical Site Infection Rates in Seven Cities in Vietnam: Findings of the International Nosocomial Infection Control Consortium.

BACKGROUND: Surgical site infections (SSIs) are the most common healthcare-associated infections (HAI) in lower-income countries. This is the first study to report the results of surveillance on SSI stratified by surgical procedure in seven Vietnamese cities. METHODS: This was a prospective, active SSI surveillance study conducted from November 2008-December 2010 in seven hospitals using the U.S. Centers for Disease Control and Prevention's National Healthcare Safety Network (CDC-NHSN) definitions and methods. Surgical procedures (SPs) were classified into 26 types according to the International Classification of Diseases Edition 9 criteria. RESULTS: We recorded 241 SSIs, associated with 4,413 SPs (relative risk [RR] 5.5%; 95% confidence interval [95% CI] 4.8-6.2). The highest SSI rates were found for limb amputation (25%), colon surgery (33%), and small bowel surgery (21%). Compared with CDC-NHSN SSI report, our SSI rates were higher for the following SPs: Limb amputation (25% vs. 1.3%; RR 20.0; p = 0.001); appendix surgery (8.8% vs. 3.5%; RR 2.54; 95% CI 1.3-5.1; p = 0.001); gallbladder surgery (13.7% vs. 1.7%; RR 7.76; 95% CI 1.9-32.1; p = 0.001); colon surgery (18.2% vs. 4.0%; RR 4.56; 95% CI 2.0-10.2; p = 0.001); open reduction of fracture (15.8% vs. 3.4%; RR 4.70, 95% CI 1.5-15.2; p = 0.004); gastric surgery (7.3% vs. 1.7%; RR 4.26; 95% CI 2.2-8.4, p = 0.001); kidney surgery (8.9% vs. 0.9%; RR 10.2; 95% CI 3.8-27.4; p = 0.001); prostate surgery (5.1% vs. 0.9%; RR 5.71; 95% CI 1.9-17.4; p = 0.001); small bowel surgery (20.8% vs. 6.7%; RR 3.07; 95% CI 1.7-5.6; p = 0.001); thyroid or parathyroid surgery (2.4% vs. 0.3%; RR 9.27; 95% CI 1.0-89.1; p = 0.019); and vaginal hysterectomy (14.3% vs. 1.2%; RR 12.3; 95% CI 1.7-88.4; p = 0.001). CONCLUSIONS: Our SSIs rates were significantly higher for 11 of the 26 types of SPs than for the CDC-NHSN. This study advances our knowledge of SSI epidemiology in Vietnam and will allow us to introduce targeted interventions.

Surgical site infections, International Nosocomial Infection Control Consortium (INICC) report, data summary of 30 countries, 2005-2010.

OBJECTIVE: To report the results of a surveillance study on surgical site infections (SSIs) conducted by the International Nosocomial Infection Control Consortium (INICC). DESIGN: Cohort prospective multinational multicenter surveillance study. SETTING: Eighty-two hospitals of 66 cities in 30 countries (Argentina, Brazil, Colombia, Cuba, Dominican Republic, Egypt, Greece, India, Kosovo, Lebanon, Lithuania, Macedonia, Malaysia, Mexico, Morocco, Pakistan, Panama, Peru, Philippines, Poland, Salvador, Saudi Arabia, Serbia, Singapore, Slovakia, Sudan, Thailand, Turkey, Uruguay, and Vietnam) from 4 continents (America, Asia, Africa, and Europe). PATIENTS: Patients undergoing surgical procedures (SPs) from January 2005 to December 2010. METHODS: Data were gathered and recorded from patients hospitalized in INICC member hospitals by using the methods and definitions of the Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN) for SSI. SPs were classified into 31 types according to International Classification of Diseases, Ninth Revision, criteria. RESULTS: We gathered data from 7,523 SSIs associated with 260,973 SPs. SSI rates were significantly higher for most SPs in INICC hospitals compared with CDC-NHSN data, including the rates of SSI after hip prosthesis (2.6% vs. 1.3%; relative risk [RR], 2.06 [95% confidence interval (CI), 1.8-2.4]; P < .001), coronary bypass with chest and donor incision (4.5% vs. 2.9%; RR, 1.52 [95% CI, 1.4-1.6]; [P < .001); abdominal hysterectomy (2.7% vs. 1.6%; RR, 1.66 [95% CI, 1.4-2.0]; P < .001); exploratory abdominal surgery (4.1% vs. 2.0%; RR, 2.05 [95% CI, 1.6-2.6]; P < .001); ventricular shunt, 12.9% vs. 5.6% (RR, 2.3 [95% CI, 1.9-2.6]; P < .001, and others. CONCLUSIONS: SSI rates were higher for most SPs in INICC hospitals compared with CDC-NHSN data.

Atmospheric heavy metal deposition in Northern Vietnam: Hanoi and Thainguyen case study using the moss biomonitoring technique, INAA and AAS.

BACKGROUND, AIM, AND SCOPE: The moss technique is widely used to monitor atmospheric deposition of heavy metals in many countries in Europe, whereas this technique is scarcely used in Asia. To implement this international reliable and cheap methodology in the Asian countries, it is necessary to find proper moss types typical for the Asian environment and suitable for the biomonitoring purposes. Such a case study was undertaken in Vietnam for assessing the environmental situation in strongly contaminated areas using local species of moss Barbula indica. MATERIALS AND METHODS: The study is focused on two areas characterized by different pollution sources: the Hanoi urban area and the Thainguyen metallurgical zone. Fifty-four moss samples were collected there according to standard sampling procedure adopted in Europe. Two complementary analytical techniques, atomic absorption spectrometry (AAS) and instrumental neutron activation analysis (INAA), were used for determination of elemental concentrations in moss samples. To characterize the pollution sources, multivariate statistical analysis was applied. RESULTS AND DISCUSSION: A total of 38 metal elements were determined in the moss by the two analytical techniques. The results of descriptive statistics of metal concentration in moss from the city center and periphery of Hanoi determined by AAS are presented. The similar results for moss from Thainguyen province determined by INAA and AAS are given also. A comparison of mean elemental concentrations in moss of this work with those in different environmental conditions of other authors provides reasonable information on heavy metal atmospheric deposition levels. Factor loadings and factor scores were used to identify and apportion contamination sources at the sampling sites. The values of percentage of total of factors show two highly different types of pollution in the two examined areas-the Hanoi pollution composition with high portion of urban-traffic activity and soil dust (62%), and the one of Thainguyen with factors related to industrial activities (75%). Besides, the scatter of factors in factor planes represents the greater diversity of activities in Hanoi than in Thainguyen. CONCLUSIONS: Good relationship between the result of factor analysis and the pollution sources evidences that the moss technique is a potential method to assess the air quality in Vietnam. RECOMMENDATIONS AND PERSPECTIVES: Moss B. indica widely distributed in Vietnam and Indo-China is shown to be a reliable bryophyte for biomonitoring purposes in sub-tropic and tropic climate. However, the necessity of moss interspecies calibration is obvious for further studies in the area to provide results compatible with those for other Asian countries and Europe.