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In this study, exfoliated graphene-decorated cobalt ferrite was fabricated and used as an adsorbent toward Congo Red dye. The relationship between the adsorption parameters and the dye removal from the aqueous solution was explored using response surface methodology. We found that the removal efficiency using the decorated adsorbent far surpassed that obtained using non-decorated ferrite materials. In addition, to achieve maximal removal efficiency against Congo Red dye (87.46%) using the as-synthesized adsorbent, experimental parameters should consist of initial dye concentration of 58.20 mg.L−1, contact time of 189 min and pH of 6.05. ANOVA analysis results indicate that the model is statistically significant because the high R2 and low P-value. Validation experiments further confirm those results.

In this paper, a potentiality of magnetic expanded graphite material (EG@CoFe2O4) for the adsorptive removal of Congo red, an anionic azo dye, from aqueous solution was studied. The experiments were carried out in batch mode in which various experimental conditions including contact time, initial dye concentration, adsorbent dosage and pH were varied and their influences on the adsorption yield were investigated. The surface of the adsorbent before and after the removal of the dye was characterized by using FT-IR analysis. Maximum adsorption of dye was achieved at pH 6. The adsorption capacity of Congo red onto EG@CoFe2O4 was found to be as high as 101.2 (mg/g), which is higher than the adsorption capacity of the CoFe2O4 (45.7 (mg/g)). These results suggested the use of expanded graphite materials as an efficient adsorbent for decontamination of Congo red dye from factory effluents.

In the present study, we developed an optimization model of CR adsorption onto EG using response surface methodology (RSM) as a statistical tool. The EG was structurally characterized using several techniques such as scanning electron microscope (SEM), estimation of N2 adsorption/desorption isotherm and plotting of pore size. The EG was used as adsorbent to remove the CR from water. Three variables involving concentration (20-50 mg/L), pH (4-10), adsorption time (0-210 min) were investigated. To find out the optimal condition, we adopted Design Expert software-based RSM for the experimental design, 3D surface plotting, and optimization. The optimal results were found at concentration of 48.3 mg/L, and contact time of 188 min for the highest CR adsorption capacity at 53.423 mg/g. With high compatibility via confirmation test, it is suggested that the RSM can be the suitable method to optimize the adsorption of CR onto EG

Herein, we reported a facile method to fabricate the exfoliated graphite (EG) by Hummer’s method via a two-step procedure including intercalation with a mixture of oxidants (H2O2 and H2SO4), and exfoliation using a microwave system. For the adsorption experiments, effect of contact time (0–210 min), initial concentration (20–60 mg/L), pH (4–10), and EG dosage (0.3–0.7 g/L) were systematically studied. Moreover, the adsorption kinetics (pseudo-first-order, pseudo-second-order, Elovich, and Bangham) and isotherms (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were carried out to elucidate the mechanism of CR adsorption over EG. Due to high porosity (40.95 m2/g) and large maximum adsorption capacity of CR (80.775 mg/g), the EG derived from natural graphite can be an effective adsorbent for CR dye treatment in aqueous solution.

Background and objectives Treatment guidelines do not recommend antibiotic use for acute respiratory infections (ARI), except for streptococcal pharyngitis/tonsillitis and pneumonia. However, antibiotics are prescribed frequently for children with ARI, often in absence of evidence for bacterial infection. The objectives of this study were 1) to assess the appropriateness of antibiotic prescriptions for mild ARI in paediatric outpatients in relation to available guidelines and detected pathogens, 2) to assess antibiotic use on presentation using questionnaires and detection in urine 3) to assess the carriage rates and proportions of resistant intestinal Enterobacteriaceae before, during and after consultation. Materials and methods Patients were prospectively enrolled in Children’s Hospital 1, Ho Chi Minh City, Vietnam and diagnoses, prescribed therapy and outcome were recorded on first visit and on follow-up after 7 days. Respiratory bacterial and viral pathogens were detected using molecular assays. Antibiotic use before presentation was assessed using questionnaires and urine HPLC. The impact of antibiotic usage on intestinal Enterobacteriaceae was assessed with semi-quantitative culture on agar with and without antibiotics on presentation and after 7 and 28 days. Results A total of 563 patients were enrolled between February 2009 and February 2010. Antibiotics were prescribed for all except 2 of 563 patients. The majority were 2nd and 3rd generation oral cephalosporins and amoxicillin with or without clavulanic acid. Respiratory viruses were detected in respiratory specimens of 72.5% of patients. Antibiotic use was considered inappropriate in 90.1% and 67.5%, based on guidelines and detected pathogens, respectively. On presentation parents reported antibiotic use for 22% of patients, 41% of parents did not know and 37% denied antibiotic use. Among these three groups, six commonly used antibiotics were detected with HPLC in patients’ urine in 49%, 40% and 14%, respectively. Temporary selection of 3rd generation cephalosporin resistant intestinal Enterobacteriaceae during antibiotic use was observed, with co-selection of resistance to aminoglycosides and fluoroquinolones. Conclusions We report overuse and overprescription of antibiotics for uncomplicated ARI with selection of resistant intestinal Enterobacteriaceae, posing a risk for community transmission and persistence in a setting of a highly granular healthcare system and unrestricted access to antibiotics through private pharmacies. Registration This study was registered at the International Standard Randomised Controlled Trials Number registry under number ISRCTN32862422: http://www.isrctn.com/ISRCTN32862422

Highlights • The diarrhoeal disease burden in a large, prospective infant cohort in Vietnam is defined. • Minimum incidence of clinic-based diarrhoea in infants: 271/1000 infant-years. • Rotavirus was most commonly identified, followed by norovirus and bacterial pathogens. • Frequent repeat infections with the same pathogen within 1 year. • Inclusion of rotavirus in the immunization schedule for Vietnam is warranted., Summary Objectives Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children, however longitudinal community-based data on burden and aetiology are limited. The findings from a large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam are presented herein. Methods Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern Vietnam, and followed for 12 months (n = 6706). Diarrhoeal illness episodes were identified through clinic-based passive surveillance, hospital admissions, and self-reports. Results The minimum incidence of diarrhoeal illness in the first year of life was 271/1000 infant-years of observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50% of positive samples), followed by norovirus (24%), Campylobacter (20%), Salmonella (18%), and Shigella (16%). Repeat infections were identified in 9% of infants infected with rotavirus, norovirus, Shigella, or Campylobacter, and 13% of those with Salmonella infections. Conclusions The minimum incidence of diarrhoeal disease in infants in both urban and semi-rural settings in southern Vietnam was quantified prospectively. A large proportion of laboratory-diagnosed disease was caused by rotavirus and norovirus. These data highlight the unmet need for a rotavirus vaccine in Vietnam and provide evidence of the previously unrecognized burden of norovirus in infants.

Isolates of Salmonella enterica serovar Typhi that are multidrug resistant (MDR, resistant to chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) and have reduced susceptibility to fluoroquinolones (nalidixic acid resistant, Na r ) are common in Asia. The optimum treatment for infections caused by such isolates is not established. This study compared different antimicrobial regimens for the treatment of MDR/Na r typhoid fever. Vietnamese children and adults with uncomplicated typhoid fever were entered into an open randomized controlled trial. Ofloxacin (20 mg/kg of body weight/day for 7 days), azithromycin (10 mg/kg/day for 7 days), and ofloxacin (15 mg/kg/day for 7 days) combined with azithromycin (10 mg/kg/day for the first 3 days) were compared. Of the 241 enrolled patients, 187 were eligible for analysis (186 S. enterica serovar Typhi, 1 Salmonella enterica serovar Paratyphi A). Eighty-seven percent (163/187) of the patients were children; of the S. enterica serovar Typhi isolates, 88% (165/187) were MDR and 93% (173/187) were Na r . The clinical cure rate was 64% (40/63) with ofloxacin, 76% (47/62) with ofloxacin-azithromycin, and 82% (51/62) with azithromycin ( P = 0.053). The mean (95% confidence interval [CI]) fever clearance time for patients treated with azithromycin (5.8 days [5.1 to 6.5 days]) was shorter than that for patients treated with ofloxacin-azithromycin (7.1 days [6.2 to 8.1 days]) and ofloxacin (8.2 days [7.2 to 9.2 days]) ( P < 0.001). Positive fecal carriage immediately posttreatment was detected in 19.4% (12/62) of patients treated with ofloxacin, 6.5% (4/62) of those treated with the combination, and 1.6% (1/62) of those treated with azithromycin ( P = 0.006). Both antibiotics were well tolerated. Uncomplicated typhoid fever due to isolates of MDR S. enterica serovar Typhi with reduced susceptibility to fluoroquinolones (Na r ) can be successfully treated with a 7-day course of azithromycin.

Real-time polymerase chain reaction (PCR) can be considered the gold standard for detection of influenza viruses due to its high sensitivity and specificity. Roche has developed the RealTime ready Influenza A/H1N1 Detection Set, consisting of a generic influenza virus A PCR targeting the M2 gene (M2 PCR) and a specific PCR targeting the hemagglutinin (HA) of A/H1N1-pdm09 (HA PCR, 2009 H1N1), with the intention to make a reliable, rapid, and simple test to detect and quantify 2009 H1N1 in clinical samples. We evaluated this kit against the US Centers for Disease Control and Prevention (USCDC)/World Health Organization real-time PCR for influenza virus using 419 nose and throat swabs from 210 patients collected in 3 large hospitals in Ho Chi Minh City, Vietnam. In the per-patient analysis, when compared to CDC PCR, the sensitivity and specificity of the M2 PCR were 85.8% and 97.6%, respectively; the sensitivity and specificity of HA PCR were 88.2% and 100%, respectively. In the per-sample analysis, the sensitivity and specificity in nose swabs were higher than those in throat swabs for both M2 and HA PCRs. The viral loads as determined with the M2 and HA PCRs correlated well with the Ct values of the CDC PCR. Compared with the CDC PCR, the kit has a reasonable sensitivity and very good specificity for the detection and quantification of influenza A virus and A/H1N1-pdm09. However, given the current status of 2009 H1N1, a kit that can detect all circulating seasonal influenza viruses would be preferable. © 2012 Elsevier Inc.

Background Hand foot and mouth disease (HFMD) is a disease of public health importance across the Asia-Pacific region. The disease is caused by enteroviruses (EVs), in particular enterovirus A71 (EV-A71). In EV-A71-associated HFMD, the infection is sometimes associated with severe manifestations including neurological involvement and fatal outcome. The availability of a robust diagnostic assay to distinguish EV-A71 from other EVs is important for patient management and outbreak response. Methods We developed and validated an internally controlled one-step single-tube real-time RT-PCR in terms of sensitivity, linearity, precision, and specificity for simultaneous detection of EVs and EV-A71. Subsequently, the assay was then applied on throat and rectal swabs sampled from 434 HFMD patients. Results The assay was evaluated using both plasmid DNA and viral RNA and has shown to be reproducible with a maximum assay variation of 4.41 % and sensitive with a limit of detection less than 10 copies of target template per reaction, while cross-reactivity with other EV serotypes was not observed. When compared against a published VP1 nested RT-PCR using 112 diagnostic throat and rectal swabs from 112 children with a clinical diagnosis of HFMD during 2014, the multiplex assay had a higher sensitivity and 100 % concordance with sequencing results which showed EVs in 77/112 (68.8 %) and EV-A71 in 7/112 (6.3 %). When applied to clinical diagnostics for 322 children, the assay detected EVs in throat swabs of 257/322 (79.8 %) of which EV-A71 was detected in 36/322 (11.2 %) children. The detection rate increased to 93.5 % (301/322) and 13.4 % (43/322) for EVs and EV-A71, respectively, when rectal swabs from 65 throat-negative children were further analyzed. Conclusion We have successfully developed and validated a sensitive internally controlled multiplex assay for rapid detection of EVs and EV-A71, which is useful for clinical management and outbreak control of HFMD. Electronic supplementary material The online version of this article (doi:10.1186/s12985-015-0316-2) contains supplementary material, which is available to authorized users.

Supplemental Digital Content is available in the text., Background: Understanding viral etiology and age-specific incidence of acute respiratory infections in infants can help identify risk groups and inform vaccine delivery, but community-based data is lacking from tropical settings. Methods: One thousand four hundred and seventy-eight infants in urban Ho Chi Minh City and 981 infants in a semi-rural district in southern Vietnam were enrolled at birth and followed to 1 year of age. Acute respiratory infection (ARI) episodes were identified through clinic-based illness surveillance, hospital admissions and self-reports. Nasopharyngeal swabs were collected from infants with respiratory symptoms and tested for 14 respiratory pathogens using multiplex reverse transcription-polymerase chain reaction. Results: Estimated incidence of ARI was 542 and 2691 per 1000 infant-years, and hospitalization rates for ARI were 81 and 138 per 1000 infant-years, in urban and semi-rural cohorts, respectively, from clinic- and hospital-based surveillance. However self-reported ARI episodes were just 1.5-fold higher in the semi-rural versus urban cohort, indicating that part of the urban–rural difference was explained by under-ascertainment in the urban cohort. Incidence was higher in infants ≥6 months of age than

Background Human respiratory syncytial virus (RSV) is an important community and nosocomial pathogen in developed countries but data regarding the importance of RSV in developing countries are relatively scarce. Methods During a 1-year surveillance study in 2010, we took serial samples from children admitted to the Emergency Unit of the Respiratory Ward of Children's Hospital 1 in Ho Chi Minh City, Vietnam. RSV was detected within 72 hours of admission to the ward in 26% (376/1439; RSV A: n = 320; RSV B: n = 54; and RSV A and B: n = 2). Among those negative in the first 72 hours after admission, 6·6% (25/377) acquired nosocomial RSV infection during hospitalization (RSV A: n = 22; and RSV B: n = 3). Results Children with nosocomial RSV infection were younger (P = 0·001) and had a longer duration of hospitalization (P

Background Iatrogenic skin and soft tissue infections by rapidly growing mycobacteria are described with increasing frequency, especially among immunocompromised patients. Case presentation Here, we present an immunocompetent patient with extensive Mycobacterium fortuitum skin and soft tissue infections after subcutaneous injections to relieve joint pains by a Vietnamese traditional medicine practitioner. Moreover, we present dilemmas faced in less resourceful settings, influencing patient management. Conclusion This case illustrates the pathogenic potential of rapid growing mycobacteria in medical or non-medical skin penetrating procedures, their world-wide distribution and demonstrates the dilemmas faced in settings with fewer resources. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0550-z) contains supplementary material, which is available to authorized users.

BACKGROUND: In Ho Chi Minh City, Vietnam, more than one-third of admissions to the two paediatric hospitals are attributable to four infectious syndromes: dengue, diarrhoeal disease, acute respiratory infection, and hand, foot and mouth disease. We have established a large prospective birth cohort study to investigate individual, environmental, virological, and immunological determinants of infection and disease in infants. Specific research questions are focused on the role of maternal antibody in protection against infection in infancy, and the adaptive immune response to vaccination and natural infection. This paper presents the cohort design, methods, and baseline characteristics of the participants enrolled in the first two years. METHODS/DESIGN: Women are enrolled prior to delivery at one hospital in each of two catchment areas: an urban district in central HCMC, and a mixed urban/rural district in the Mekong Delta 150 km southwest of HCMC. Infants are enrolled within 3 days of birth, and maternal and cord blood samples are collected. Routine blood samples and data on growth, health status and vaccinations are collected from infants at scheduled visits at 4, 9 and 12 months. Clinical data and specimens are collected from infants presenting at a study clinic, or admitted to hospital, with any of the the four infectious syndromes of interest. DISCUSSION: In four years since since the study began in July 2009, >6400 infants have been enrolled, and enrolment is ongoing. Attrition is low: 84% of participants have completed the full 12-month follow-up period. Baseline characteristics of the first 4300 enrollees are presented here. We have demonstrated the feasibility of establishing a large prospective study of infectious diseases in infancy in a resource-limited setting, with minimal loss to follow-up. Our linked socio-demographic, clinical and laboratory data will help elucidate the viral aetiology and epidemiology of common infectious diseases of infancy, and can inform the implemention of existing and future vaccines. This study furthermore provides a platform to which additional endpoints could be added in the future.

Acute central nervous system (CNS) infections cause substantial morbidity and mortality, but the etiology remains unknown in a large proportion of cases. We identified and characterized the full genome of a novel cyclovirus (tentatively named cyclovirus-Vietnam [CyCV-VN]) in cerebrospinal fluid (CSF) specimens of two Vietnamese patients with CNS infections of unknown etiology. CyCV-VN was subsequently detected in 4% of 642 CSF specimens from Vietnamese patients with suspected CNS infections and none of 122 CSFs from patients with noninfectious neurological disorders. Detection rates were similar in patients with CNS infections of unknown etiology and those in whom other pathogens were detected. A similar detection rate in feces from healthy children suggested food-borne or orofecal transmission routes, while high detection rates in feces from pigs and poultry (average, 58%) suggested the existence of animal reservoirs for such transmission. Further research is needed to address the epidemiology and pathogenicity of this novel, potentially zoonotic virus., IMPORTANCE Acute central nervous system (CNS) infections cause substantial morbidity and mortality, but the etiology frequently remains unknown, which hampers development of therapeutic or preventive strategies. Hence, identification of novel pathogens is essential and is facilitated by current next-generation sequencing-based methods. Using such technology, we identified and characterized the full genome of a novel cyclovirus in cerebrospinal fluid (CSF) specimens from two Vietnamese patients with CNS infections of unknown etiology, which was subsequently detected in none of 122 CSF specimens from patients with noninfectious neurological disorders but 4% of 642 CSF specimens from Vietnamese patients with suspected or confirmed CNS infections. Similar detection rates in feces from healthy children suggested food-borne or orofecal transmission routes, while frequent detection in feces from Vietnamese pigs and poultry (average, 58%) suggested the existence of animal reservoirs for such transmission. Further studies are needed to address the epidemiology and pathogenicity of this novel, potentially zoonotic virus.

Hypovolemic shock (dengue shock syndrome (DSS)) is the most common life-threatening complication of dengue. We conducted a genome-wide association study of 2,008 pediatric cases treated for DSS and 2,018 controls from Vietnam. Replication of the most significantly associated markers was carried out in an independent Vietnamese sample of 1,737 cases and 2,934 controls. SNPs at two loci showed genome-wide significant association with DSS. We identified a susceptibility locus at MICB (major histocompatibility complex (MHC) class I polypeptide-related sequence B), which was within the broad MHC region on chromosome 6 but outside the class I and class II HLA loci (rs3132468, P meta = 4.41 × 10 -11, per-allele odds ratio (OR) = 1.34 (95% confidence interval: 1.23-1.46)). We identified associated variants within PLCE1 (phospholipase C, epsilon 1) on chromosome 10 (rs3765524, P meta = 3.08 × 10 -10, per-allele OR = 0.80 (95% confidence interval: 0.75-0.86)). We identify two loci associated with susceptibility to DSS in people with dengue, suggesting possible mechanisms for this severe complication of dengue. © 2011 Nature America, Inc. All rights reserved.

Diarrhea is a major cause of childhood morbidity and mortality in developing countries, and the majority of infections are of viral etiology. We aimed to compare the etiological prevalence of the major enteric viruses in an urban and a rural setting in southern Vietnam. We simultaneously screened fecal specimens from 362 children in Ho Chi Minh City and Dong Thap province that were hospitalized with acute diarrhea over a 1-month-long period for four viral gastrointestinal pathogens. Rotavirus was the most common pathogen identified, but there was a differential prevalence of rotavirus and norovirus between the urban and rural locations. Furthermore, rotavirus genotyping and phylogenetic analysis again differentiated the genotypes by the sampling location. Our data show a disproportional distribution of enteric viral pathogens in urban and rural locations, and we provide evidence of continual importation of new rotavirus strains into southern Vietnam and report the emergence of rotavirus genotype G12.

Background Infants account for a small proportion of the overall dengue case burden in endemic countries but can be clinically more difficult to manage. The clinical and laboratory features in infants with dengue have not been extensively characterised. Methodology/Principal Findings This prospective, cross-sectional descriptive study of infants hospitalized with dengue was conducted in Vietnam from November 2004 to December 2007. More than two-thirds of 303 infants enrolled on clinical suspicion of dengue had a serologically confirmed dengue virus (DENV) infection. Almost all were primary dengue infections and 80% of the infants developed DHF/DSS. At the time of presentation and during hospitalization, the clinical signs and symptoms in infants with dengue were difficult to distinguish from those with other febrile illnesses, suggesting that in infants early laboratory confirmation could assist appropriate management. Detection of plasma NS1 antigen was found to be a sensitive marker of acute dengue in infants with primary infection, especially in the first few days of illness. Conclusions/Significance Collectively, these results provide a systematic description of the clinical features of dengue in infants and highlight the value of NS1 detection for diagnosis., Author Summary Dengue is a major public health problem in tropical and subtropical countries, including Vietnam. Dengue cases occur in children and young adults; however, severe dengue also occurs in infants less than 1 year of age. Prompt recognition of dengue is important for appropriate case management, particularly in infants in whom febrile illness from other causes is common. We describe the clinical picture, virological and immunological characteristics of infants with dengue admitted to three hospitals in southern Vietnam, compared with infants admitted with fever not due to dengue. We show that infants with dengue are difficult to distinguish from those with other febrile illnesses based on signs and symptoms at presentation, and so laboratory tests to confirm dengue virus infection may be useful for diagnosis and management. Conventional diagnostic methods for dengue have low sensitivity early in infection, and we show that an alternative antigen-detection assay that has demonstrated good sensitivity and specificity in older age groups also performs well in infants. This study will help to inform the diagnosis and management of dengue in infants.

Background Shigellosis remains considerable public health problem in some developing countries. The nature of Shigellae suggests that they are highly adaptable when placed under selective pressure in a human population. This is demonstrated by variation and fluctuations in serotypes and antimicrobial resistance profile of organisms circulating in differing setting in endemic locations. Antimicrobial resistance in the genus Shigella is a constant threat, with reports of organisms in Asia being resistant to multiple antimicrobials and new generation therapies. Methods Here we compare microbiological, clinical and epidemiological data from patients with shigellosis over three different periods in southern Vietnam spanning14 years. Results Our data demonstrates a shift in dominant infecting species (S. flexneri to S. sonnei) and resistance profile of the organisms circulating in southern Vietnam. We find that there was no significant variation in the syndromes associated with either S. sonnei or S. flexneri, yet the clinical features of the disease are more severe in later observations. Conclusions Our findings show a change in clinical presentation of shigellosis in this setting, as the disease may be now more pronounced, this is concurrent with a change in antimicrobial resistance profile. These data highlight the socio-economic development of southern Vietnam and should guide future vaccine development and deployment strategies. Trial Registration Current Controlled Trials ISRCTN55945881

This research study investigates the similarities and differences in assessment policy, perspectives and practices in relation to student learning, desirable graduate outcomes and lifelong learning (LLL) in two departments with similar disciplines: Sociology and Social Policy and English Studies of the Midlands University (MU) – UK and Sociology and English Linguistics and Literature of the Ho Chi Minh City University (HCMU) – Vietnam. The study’s conceptual framework was developed from research literatures on assessment, mainly David Boud’s framework of sustainable assessment or assessment for longer term learning, as the framework for data analysis. The methodology is a comparative case study, and the methods include using semi-structured interviews with 22 staff in both cases, four student focus groups, an action-based intervention at the English department of the HCMU, and document analysis. The similarities and differences across the comparative cases are explained on the basis of the economic, socio-cultural and HE contexts, while Boud’s framework is reframed theoretically and operationally for these contexts, and as a guide to improving practices. The data shows that although more elements of Boud’s framework were found in the MU than the HCMU, assessment in both cases was an imperfect realisation of this framework. The argument is made that this framework can offer a good vision for the two cases to aim at in terms of changes in their assessment perspective and practices, but the framework itself should also be reframed with contextual and cultural features of assessment, as well as the development of human capabilities and functionings in order to encompass a fuller range of educational goals. It is concluded that above all assessment should support not only learning at university but also expansive rather than reductive LLL.