Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Curr Issues Mol Biol ; 46(3): 1768-1776, 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38534732

RESUMEN

Prodigiosin, a red pigment produced by numerous bacterial species, exerts various antibiotic effects on prokaryotic and eukaryotic organisms. For instance, human carcinoma cell lines appear to suffer from endoplasmic reticulum (ER) stress in the presence of prodigiosin. Here, we demonstrated that prodigiosin also triggers the unfolded-protein response (UPR), which is a cytoprotective response against ER stress, in yeast Saccharomyces cerevisiae. An S. cerevisiae mutant carrying a UPR-deficient mutation was hypersensitive to prodigiosin. Our observations cumulatively indicate that protein folding in the ER is impaired by prodigiosin, illustrating a new mode of action.

2.
Molecules ; 27(9)2022 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-35566220

RESUMEN

Lichen-derived monoaromatic compounds are bioactive compounds, associated with various pharmacological properties: antioxidant, antifungal, antiviral, cytotoxicity, and enzyme inhibition. However, little is known about data regarding alpha-glucosidase inhibition and antimicrobial activity. Very few compounds were reported to have these activities. In this paper, a series of monoaromatic compounds from a lichen source were isolated and structurally elucidated. They are 3,5-dihydroxybenzoic acid (1), 3,5-dihydroxybenzoate methyl (2), 3,5-dihydroxy-4-methylbenzoic acid (3), 3,5-dihydroxy-4-methoxylbenzoic acid (4), 3-hydroxyorcinol (5), atranol (6), and methyl hematommate (7). To obtain more derivatives, available compounds from the previous reports such as methyl ß-orsellinate (8), methyl orsellinate (9), and D-montagnetol (10) were selected for bromination. Electrophilic bromination was applied to 8-10 using NaBr/H2O2 reagents to yield products methyl 5-bromo-ß-orsellinate (8a), methyl 3,5-dibromo-orsellinate (9a), 3-bromo-D-montagnetol (10a), and 3,5-dibromo-D-montagnetol (10b). Compounds were evaluated for alpha-glucosidase inhibition and antimicrobial activity against antibiotic-resistant, pathogenic bacteria Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii. Compound 4 showed stronger alpha-glucosidase inhibition than others with an IC50 value of 24.0 µg/mL. Synthetic compound 9a exhibited remarkable activity against Staphylococcus aureus with a MIC value of 4 µg/mL. Molecular docking studies were performed to confirm the consistency between in vitro and in silico studies.


Asunto(s)
Líquenes , alfa-Glucosidasas , Antibacterianos/farmacología , Peróxido de Hidrógeno , Simulación del Acoplamiento Molecular , Staphylococcus aureus
3.
Chemistry ; 25(22): 5777-5786, 2019 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-30746784

RESUMEN

The hexapyrrole-α,ω-dicarbaldehydes 1 a and 1 b were metallated with CuII , NiII , and PdII to give bimetallic complexes where a pair of 3 N+O four-coordinate metal planes are helically distorted and the central 2,2'-bipyrrole subunit adopts a cis or trans conformation. X-ray crystallographic analysis of the bisCu complex revealed a closed form with a cis-2,2'-bipyrrole subunit and an open form with a trans-2,2'-bipyrrole subunit. The bisPd complexes took a closed form both in the solid state and in solution. They are regarded as single helicates of two turns and the energy barrier for the interchange between an M helix and a P helix was remarkably influenced by the bulky 3,3'-substituent of the central 2,2'-bipyrrole subunit. Although the bisNi complexes adopt a closed form in the solid state, they exist as a homohelical open C2 -symmetric form or a heterohelical open Ci -symmetric form in solution. A theoretical study suggested that the closed form of 1 aPd was stabilized by the Pd-Pd interaction. Compound 1 aPd was reversibly oxidized by one electron at 0.14 V versus ferrocene/ferrocenium (Fc/Fc+ ) and this oxidized species showed Vis/NIR absorption bands at λ=767 and 1408 nm.

4.
BMC Infect Dis ; 17(1): 333, 2017 05 08.
Artículo en Inglés | MEDLINE | ID: mdl-28482808

RESUMEN

BACKGROUND: In 2011-2012, Northern Vietnam experienced its first large scale hand foot and mouth disease (HFMD) epidemic. In 2011, a major HFMD epidemic was also reported in South Vietnam with fatal cases. This 2011-2012 outbreak was the first one to occur in North Vietnam providing grounds to study the etiology, origin and dynamic of the disease. We report here the analysis of the VP1 gene of strains isolated throughout North Vietnam during the 2011-2012 outbreak and before. METHODS: The VP1 gene of 106 EV-A71 isolates from North Vietnam and 2 from Central Vietnam were sequenced. Sequence alignments were analyzed at the nucleic acid and protein level. Gene polymorphism was also analyzed. A Factorial Correspondence Analysis was performed to correlate amino acid mutations with clinical parameters. RESULTS: The sequences were distributed into four phylogenetic clusters. Three clusters corresponded to the subgenogroup C4 and the last one corresponded to the subgenogroup C5. Each cluster displayed different polymorphism characteristics. Proteins were highly conserved but three sites bearing only Isoleucine (I) or Valine (V) were characterized. The isoleucine/valine variability matched the clusters. Spatiotemporal analysis of the I/V variants showed that all variants which emerged in 2011 and then in 2012 were not the same but were all present in the region prior to the 2011-2012 outbreak. Some correlation was found between certain I/V variants and ethnicity and severity. CONCLUSIONS: The 2011-2012 outbreak was not caused by an exogenous strain coming from South Vietnam or elsewhere but by strains already present and circulating at low level in North Vietnam. However, what triggered the outbreak remains unclear. A selective pressure is applied on I/V variants which matches the genetic clusters. I/V variants were shown on other viruses to correlate with pathogenicity. This should be investigated in EV-A71. I/V variants are an easy and efficient way to survey and identify circulating EV-A71 strains.


Asunto(s)
Proteínas de la Cápside/genética , Enterovirus Humano A/genética , Enfermedad de Boca, Mano y Pie/virología , Preescolar , Brotes de Enfermedades , Enterovirus/aislamiento & purificación , Enterovirus Humano A/aislamiento & purificación , Enterovirus Humano A/patogenicidad , Epidemias , Femenino , Enfermedad de Boca, Mano y Pie/epidemiología , Humanos , Lactante , Isoleucina , Masculino , Mutación , Filogenia , Polimorfismo Genético , Selección Genética , Análisis Espacio-Temporal , Valina , Vietnam/epidemiología
5.
BMC Public Health ; 16(1): 777, 2016 08 11.
Artículo en Inglés | MEDLINE | ID: mdl-27514373

RESUMEN

BACKGROUND: Rotavirus is the most common etiology of diarrhea-associated hospitalizations and clinic visits in Vietnamese children < 5 years old. To estimate the economic burden of rotavirus-associated formal healthcare encounters, an economic study was conducted. METHODS: A cost-of-illness study was performed from a societal perspective. Data were collected from children below the age of five years who presented to a clinic or hospital with symptoms of acute gastroenteritis (AGE). Patient-specific information on resource use and cost was obtained through caregiver interviews and medical chart review. Costs are presented in 2014 US dollar ($). RESULTS: A total of 557 children with symptoms of AGE were enrolled from March through June 2009, with mean age of 16.5 months. Of the 340 outpatients and 217 admitted patients enrolled, 41 % tested rotavirus positive. It was found that, from a societal perspective, the mean total cost of AGE was $175. Costs of patients with and without rotavirus were $217 and $158, respectively. From multiple regression analysis, it was found that rotavirus infection, patient age and receiving oral rehydration solution before visiting health facility had significant effect on the costs. CONCLUSIONS: This study clearly demonstrated substantial economic burden of AGE including rotavirus disease. They were significantly greater than the previously reported cost estimates in Vietnam. These updated costs of illness result in more favorable vaccine cost-effectiveness than in previous economic evaluations.


Asunto(s)
Costo de Enfermedad , Diarrea/economía , Gastroenteritis/economía , Infecciones por Rotavirus/economía , Vacunación/economía , Diarrea/prevención & control , Diarrea/virología , Femenino , Gastroenteritis/prevención & control , Gastroenteritis/virología , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Masculino , Rotavirus , Infecciones por Rotavirus/prevención & control , Infecciones por Rotavirus/virología , Vacunas contra Rotavirus/economía , Vietnam
6.
Hum Antibodies ; 31(1-2): 9-17, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37248893

RESUMEN

BACKGROUND: Postural Orthostatic Tachycardia Syndrome (POTS) is a common condition affecting more than 170 people per 100,000 population. However, POTS following COVID-19 vaccination remains a rare reporting in the medical literature. OBJECTIVE: We, herein, summarize and highlight the evidence that has been reported regarding POTS-like symptoms following COVID-19 vaccination. METHODS: We conducted a literature search and summarized the findings in the form of a narrative commentary. All types of publications (case reports/series, original articles, letters to editors, brief communications etc.) in English language were included. RESULTS: Whilst the exact pathogenetic mechanism behind POTS is yet to elucidated, there has been increasing evidence pointing towards an autoimmune dysfunction. Females were found to be predominantly affected (72%) with age range from 17 years to 52 years. Additionally, it seems that POTS-like symptoms could be triggered after immunization with Pfizer- BioNTech, Moderna, and Oxford-AstraZeneca COVID-19 vaccines. The symptoms typically appear within the first week, depending upon previous exposure to the virus and presence of other systemic conditions. In some patients, the condition is self-resolving. However, in others, non-pharmacological interventions coupled with negative ionotropic medications can be used for symptomatic management of the patients. CONCLUSIONS: Timely diagnosis and proper treatment are quintessential for ensuring early alleviation (and in some cases complete resolution) of symptoms. Furthermore, there may be episodes of relapse. Overall prognosis of the new-onset POTS-like symptoms is difficult to predict based on current literature.


Asunto(s)
Vacunas contra la COVID-19 , COVID-19 , Síndrome de Taquicardia Postural Ortostática , Adolescente , Femenino , Humanos , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Síndrome de Taquicardia Postural Ortostática/etiología , Síndrome de Taquicardia Postural Ortostática/diagnóstico , Vacunación/efectos adversos
7.
Biomed Res Int ; 2022: 4053074, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35509712

RESUMEN

Prodigiosin (Pg), a secondary metabolism produced by numerous bacterial species, is known as anticancer, antibacterial, antifungal, immunosuppressant, antioxidant, antimalarial properties. Pg has been tested for antitumor activity in many different cancer cell lines but studies in LU-1, KB cell lines, and tumor-bearing mice are still limited. In this study, Serratia marcescens QBN VTCC 910026 strain (GenBank: KX674054.1) was mutated using Ethyl Methanesulfonate (EMS) to increase the production of Pg. One strain known as EMS 5 was capable of increasing prodigiosin biosynthetic yield by 52% when compared to the wild-type strain. Red bacterial pigmented colonies containing Pg were collected from solid media, lysed with acetone, purified with toluene: ethyl acetate at a ratio of 9: 1 (v/v), and then used to evaluate the potential anticancer activity. The purity of Pg was confirmed using a high-performance liquid chromatography (HPLC) method which indicated a 98% rate. Pg chemical formula which was determined using 1H-NMR and 13C-NMR spectroscopy, confirmed as prodigiosin (Pg). Human breast cancer cell lines MCF-7, oropharyngeal cancer KB, and particularly lung cancer LU-1 in vitro were used to test the anticancer activity of purified Pg compound. It showed a strong inhibitory ability in all the cancer cell lines. Furthermore, the isolated Pg had capable of inhibiting tumor growth, the tumor volume decreased by 36.82%, after 28 days. The results indicated that the bacterial prodigiosin from variants Serratia marcescens QBN VTCC 910026 strain is an encouraging fragment suitable for therapeutic applications.


Asunto(s)
Prodigiosina , Serratia marcescens , Animales , Antibacterianos/farmacología , Antifúngicos/metabolismo , Ratones , Prodigiosina/metabolismo , Prodigiosina/farmacología , Metabolismo Secundario , Serratia marcescens/química
8.
Sci Rep ; 12(1): 20189, 2022 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-36424459

RESUMEN

The human gut microbiota has been shown to be significantly perturbed by antibiotic use, while recovering to the pre-treatment state several weeks after short antibiotic exposure. The effects of antibiotics on the gut microbiota have however been mainly documented in high-income settings with lower levels of antibiotic resistance as compared to lower and middle income countries (LMIC). This study aimed to examine the long-term consequences of repeated exposure to commonly use antibiotics on the fecal microbiota of residents living in a low income setting with high prevalence of antibiotic resistance. Fecal samples from household individuals (n = 63) participating in a rural cohort in northern Vietnam were collected monthly for a period of 6 months. Using 16S V4 rRNA gene region amplicon sequencing and linear mixed-effects models analysis, we observed only a minor and transient effect of antibiotics on the microbial richness (ß = - 31.3, 95%CI = - 55.3, - 7.3, p = 0.011), while the microbial diversity was even less affected (ß = - 0.298, 95%CI - 0.686, 0.090, p = 0.132). Principal Component Analyses (PCA) did not reveal separation of samples into distinct microbiota-based clusters by antibiotics use, suggesting the microbiota composition was not affected by the antibiotics commonly used in this population. Additionally, the fecal microbial diversity of the subjects in our study cohort was lower when compared to that of healthy Dutch adults (median 3.95 (IQR 3.72-4.13) vs median 3.69 (IQR3.31-4.11), p = 0.028, despite the higher dietary fiber content in the Vietnamese as compared to western diet. Our findings support the hypothesis that frequent antibiotic exposure may push the microbiota to a different steady state that is less diverse but more resilient to disruption by subsequent antibiotic use.


Asunto(s)
Microbioma Gastrointestinal , Adulto , Humanos , Microbioma Gastrointestinal/genética , Antibacterianos/efectos adversos , Vietnam , Estudios de Cohortes , Pueblo Asiatico
9.
Lancet Reg Health Southeast Asia ; 4: 100031, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35775040

RESUMEN

Background: Tackling the spread of COVID-19 remains a crucial part of ending the pandemic. Its highly contagious nature and constant evolution coupled with a relative lack of immunity make the virus difficult to control. For this, various strategies have been proposed and adopted including limiting contact, social isolation, vaccination, contact tracing, etc. However, given the heterogeneity in the enforcement of these strategies and constant fluctuations in the strictness levels of these strategies, it becomes challenging to assess the true impact of these strategies in controlling the spread of COVID-19. Methods: In the present study, we evaluated various transmission control measures that were imposed in 10 global urban cities and provinces in 2021- Bangkok, Gauteng, Ho Chi Minh City, Jakarta, London, Manila City, New Delhi, New York City, Singapore, and Tokyo. Findings: Based on our analysis, we herein propose the population-level Swiss cheese model for the failures and pitfalls in various strategies that each of these cities and provinces had. Furthermore, whilst all the evaluated cities and provinces took a different personalized approach to managing the pandemic, what remained common was dynamic enforcement and monitoring of breaches of each barrier of protection. The measures taken to reinforce the barriers were adjusted continuously based on the evolving epidemiological situation. Interpretation: How an individual city or province handled the pandemic profoundly affected and determined how the entire country handled the pandemic since the chain of transmission needs to be broken at the very grassroot level to achieve nationwide control. Funding: The present study did not receive any external funding.

10.
Bull World Health Organ ; 89(2): 127-36, 2011 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-21346924

RESUMEN

OBJECTIVE: To examine the association between gestational weight gain and maternal body mass index (BMI) among Vietnamese women and the risk of delivering an infant too small or too large for gestational age. METHODS: A prospective health-facility-based study of 2989 pregnant Vietnamese women was conducted in the city of Nha Trang in 2007-2008. Cubic logistic regression was used to investigate the association of interest. Infants were classified into weight-for-gestational-age categories according to weight centiles for the Asian population. Gestational age was based on the date of last menstrual period and adjusted by the results of first-trimester ultrasound. FINDINGS: BMI was low (< 18.5), normal (18.5-22.9) and high (≥ 23.0) in 26.1%, 65.4% and 8.5% of the women, respectively. In each of these BMI categories, the percentage of women who delivered infants too small for gestational age was 18.1, 10.0 and 9.4, respectively, and the mean gestational weight gain was 12.5 kg (standard deviation, SD: ± 3.6), 12.2 kg (SD: ± 3.8) and 11.5 kg (SD: ± 4.7), respectively. Among women with low BMI, the risk of delivering an infant too small for gestational age ranged from approximately 40% if the gestational weight gain was < 5 kg to 20% if it was 5-10 kg. CONCLUSION: Having a low BMI, commonly found in Viet Nam, puts women at risk of delivering an infant too small for gestational age, especially when total maternal gestational weight gain is < 10 kg.


Asunto(s)
Peso al Nacer , Índice de Masa Corporal , Edad Gestacional , Bienestar Materno , Resultado del Embarazo , Aumento de Peso , Adulto , Femenino , Humanos , Modelos Logísticos , Embarazo , Atención Prenatal , Desarrollo de Programa , Estudios Prospectivos , Factores de Riesgo , Vietnam
11.
Health Serv Insights ; 14: 1178632920988843, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33597809

RESUMEN

This study estimates the amount antiretroviral therapy (ART) clients paid out of pocket for preventive and treatment services and the percentage of ART clients incurring catastrophic payments during the period when ART services were transitioning from donor funding to domestic social health insurance (SHI) in Vietnam. Using a cross-sectional facility-based survey in 9 provinces, a sample of 582 clients across 18 ART facilities representatives of all facilities where SHI-financed ART was being implemented were interviewed in 2019. Results indicated 13.4% (95% CI: 5.7%, 28.2%) of clients incurred a payment for outpatient ART care. The average out of pocket expenditures for outpatient visits and HIV related outpatient visits was USD $71.2 and $8 per year, respectively. The average out of pocket expenditure for inpatient admission and HIV related inpatient admission was $7.1 and $1.6, respectively. Only 0.1% clients currently experienced HIV-related catastrophic payment at the 25% of total expenditures threshold. The study confirms the transition from donor-financed ART to SHI-financed ART is not causing financial hardship for ART clients. However, more commitment from the Government of Vietnam to strengthen HIV-related services under SHI may be needed in the future, and there is still need to ensure universal SHI coverage among people with HIV/AIDs in Vietnam.

12.
Mol Biotechnol ; 63(11): 1004-1015, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34185249

RESUMEN

Various studies showed that the suppression of α-glucosidase activity can impede the glucose absorption in our body, and therefore, it can be used to treat type 2 diabetes. Hence, the compounds with anti-α-glucosidase have gained considerable attention because of their potential application in diabetes treatment. In previous literature studies, these anti-α-glucosidase compounds were extracted from plants and fungus. Less studies are being conducted to identify the anti-α-glucosidase compounds in the microbial community. In this study, 23 marine bacterial strains were screened for their potential to suppress the α-glucosidase activity. The highest inhibitory activity was exhibited by isolated L06 which was identified as Oceanimonas smirnovii EBL6. The cultivation conditions, such as temperature and pH, were optimized to increase the production of α-glucosidase inhibitors by Oceanimonas smirnovii EBL6 strain. The result findings showed that the highest yield of α-glucosidase inhibitors can be obtained at the culture time of 120 h, fermentation temperature of 30 °C, and pH 4.6. Under these conditions, the inhibitory activity of α-glucosidase can reach 81%. The IC50 of n-butanol extract was 13.89 µg/ml, while standard acarbose was 31.16 µg/ml. Overall, these findings suggest that Oceanimonas smirnovii produces α-glucosidase inhibitors and could been applied in the biochemical and medicinal fields in the future.


Asunto(s)
Organismos Acuáticos/química , Inhibidores de Glicósido Hidrolasas/química , alfa-Glucosidasas/química , Aeromonadaceae/química , Técnicas de Cultivo de Célula/métodos , Medios de Cultivo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patología , Descubrimiento de Drogas , Inhibidores de Glicósido Hidrolasas/farmacología , Humanos , alfa-Glucosidasas/metabolismo
13.
J Multidiscip Healthc ; 14: 799-807, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33880029

RESUMEN

BACKGROUND: Nurses play a pivotal role in pain management. Knowing more about nurses' knowledge and attitudes regarding pain is important as we develop multidisciplinary pain services. Therefore, this study aimed to assess knowledge and attitudes regarding pain management among nurses in a geriatric hospital and its associated factors. SUBJECTS AND METHODS: A survey was conducted of nurses worked at the National Geriatric Hospital over a 3-month period. The Knowledge and Attitudes Survey Regarding Pain (KASRP) was utilized to assess nurses' knowledge and attitudes toward pain management. Four domains were defined based on KASRP, included cancer-related pain, pain assessment, pharmacology and substance abuse and physical dependence. Knowledge and attitudes regarding pain were classified as poor, fair, or good (≤50%, 50% - 75%, or ≥75% of the KASRP score). Multivariate Tobit regression models were applied to identify factors associated with the knowledge and attitudes regarding pain management. RESULTS: Of 154 participants completed the survey, 72.2% (111 participants) had poor knowledge and attitudes regarding pain management. The participants had a correct mean score of 45.2% (SD = 2.2). Nurses' knowledge of pain assessment was poor, with the proportion of correct answers to nine questions ranging from 2.6% to 50%. 44.8% of nurses reported never or rarely using pain assessment tools. Nurses who had previous training regarding pain at medical universities had significantly higher scores of knowledge and attitudes compared to those without training. Nurses who often use pain assessment tools had a significantly higher level of knowledge and attitudes than those who never or rarely use them. CONCLUSION: This study highlights significant deficits of knowledge and negative attitudes regarding pain management among nurses. The subject of pain management should be applied and enhanced in the nursing undergraduate curriculum. Nurses' active participation in pain management should be encouraged by healthcare providers for older patients.

14.
Appl Radiat Isot ; 156: 108842, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31732424

RESUMEN

The flux-weighted average cross sections of 127I(γ,xn)126,124,123I reactions were experimentally determined with the bremsstrahlung end-point energies of 50 and 70 MeV by activation and off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The 127I(γ,xn)126-121I reaction cross sections as a function of photon energy were theoretically calculated using the TALYS 1.8 code. The flux-weighted average cross sections of 127I(γ, xn)126,124,123I reactions as a function of bremsstrahlung end-point energies were also obtained from the literature and TALYS data based on mono-energetic photons and are found to be in close agreement with the present data. The experimental and theoretical 127I(γ, xn)126-121I reaction cross-sections increase with bremsstrahlung energy, which indicates the role of excitation energy. After a certain energy, the individual 127I(γ, xn)126-121I reaction cross sections decrease with increase of bremsstrahlung energy due to opening of other reactions, which indicates sharing of energy in different reaction channels. The radioactive iodine isotopes production cross-sections are important for the useful medical purpose.

15.
RSC Adv ; 10(47): 28343-28350, 2020 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-35519108

RESUMEN

We present a numerical study of thermo-tunable broadband-negative-permeability metamaterial based on second-order hybridization operating at the THz regime. The conventional metal is replaced by InSb, in which the temperature-dependent conductivity plays a key role in tuning the separation of second-order-hybridization magnetic-resonance modes. It is demonstrated that the hybridization in a simple disk-pair dimer can be tuned by temperature, leading to a significant broadening of the negative-permeability at THz frequencies. By increasing the temperature of the InSb patterns in the structure from 300 to 450 K, the fractional bandwidth (FBW) of the negative permeability curve varies from 4.4% to 12.9%. The thermally-increased carrier-density of InSb reduces the kinetic inductance, the main mechanism of the enhanced magnetic-resonance and the stronger activated-hybridization. Moreover, optimization for the bandwidth of negative permeability is also carried out by changing the geometrical parameters to have a FBW of 20.9%. The equivalent LC-circuit model and standard retrieval method are performed to elaborate our proposed idea. Our results would pave the way for the implementations of diversified semiconductors in tunable broadband-negative-permeability and broadband-negative-refractive-index metamaterials at THz frequencies.

16.
J Anal Methods Chem ; 2020: 6623511, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33489413

RESUMEN

This work investigated the removal of antibiotic tetracycline (TC) from wastewater using nanocomposite material based on laterite modified with polyanion, polystyrene sulfonate (PSS). The effective factors influenced on the TC removal using nanocomposite PSS-modified laterite (NCPML) were optimized and found to be pH 4, solid-liquid ratio 5 mg/mL, and contact time 180 min. The highest removal of TC reached about 88% under the optimum adsorption conditions. The adsorption isotherm and kinetics of TC adsorption onto NCPML were in good agreement with the Langmuir and pseudo-second-order models, respectively. The characteristics of the NCPML material before and after TC adsorption were examined by zeta (ζ) potential measurements, Brunauer-Emmett-Teller (BET) method, and Fourier transform infrared spectroscopy (FT-IR). The TC adsorption onto NCPML was induced by electrostatic interaction, hydrogen bonding, and diffusion interaction. The TC removal from wastewater was approximately 94% while efficiency still reached 66% after five regenerations. Our research reveals that NCPML is a high-performance adsorbent for TC removal from wastewater.

18.
Vaccine ; 38(52): 8273-8285, 2020 12 14.
Artículo en Inglés | MEDLINE | ID: mdl-33223308

RESUMEN

Development of multivalent hand, foot, and mouth disease (HFMD) vaccines against enterovirus A71 (EV-A71) and several non-EV-A71 enteroviruses is needed for this life-threatening disease with a huge economic burden in Asia-Pacific countries. Comprehensive studies on the molecular epidemiology and genetic and antigenic characterization of major causative enteroviruses will provide information for rational vaccine design. Compared with molecular studies on EV-A71, that for non-EV-A71 enteroviruses remain few and limited in Vietnam. Therefore, we conducted a 10-year study on the circulation and genetic characterization of coxsackievirus A16 (CV-A16) and CV-A6 isolated from patients with HFMD in Northern Vietnam between 2008 and 2017. Enteroviruses were detected in 2228 of 3212 enrolled patients. Of the 42 serotypes assigned, 28.4% and 22.4% accounted for CV-A6 and CV-A16, being the second and the third dominant serotypes after EV-A71 (31.7%), respectively. The circulation of CV-A16 and CV-A6 showed a wide geographic distribution and distinct periodicity. Phylogenetic analyses revealed that the majority of Vietnamese CV-A6 and CV-A16 strains were located within the largest sub-genotypes or sub-genogroups. These comprised strains isolated from patients with HFMD worldwide during the past decade and the Vietnamese strains have been evolving in a manner similar to the strains circulating worldwide. Amino acid sequences of the putative functional loops on VP1 and other VPs among Vietnamese CV-A6 and CV-A16 isolates were highly conserved. Moreover, the functional loop patterns of VP1 were similar to the dominant patterns found worldwide, except for the T164K substitution on the EF loop in Vietnamese CV-A16. The findings suggest that the development of a universal HFMD vaccine, at least in Vietnam, must target CV-A6 and CV-A16 as two of the three major HFMD-causing serotypes. Vietnamese isolates or their genome sequences can be considered for rational vaccine design.


Asunto(s)
Enterovirus Humano A , Enterovirus , Enfermedad de Boca, Mano y Pie , Asia , China , Enterovirus/genética , Enterovirus Humano A/genética , Enfermedad de Boca, Mano y Pie/epidemiología , Enfermedad de Boca, Mano y Pie/prevención & control , Humanos , Filogenia , Vietnam/epidemiología
19.
PLoS Negl Trop Dis ; 14(12): e0008937, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33351806

RESUMEN

BACKGROUND: Eosinophilic meningitis (EM) is a rare clinical syndrome caused by both infectious and noninfectious diseases. In tropical pacific countries, Angiostrongylus cantonensis is the most common cause. However, the EM definition varies in the literature, and its relation to parasitic meningitis (PM) remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: Adult and adolescent patients of 13 years old or above with suspected central nervous system (CNS) infections with abnormal CSF findings were prospectively enrolled at a tertiary referral hospital in Hanoi, Vietnam from June 2012 to May 2014. Patients with EM or suspected PM (EM/PM) were defined by the presence of either ≥10% eosinophils or an absolute eosinophil cell counts of ≥10/mm3 in the CSF or blood eosinophilia (>16% of WBCs) without CSF eosinophils. In total 679 patients were enrolled: 7 (1.03%) had ≥10% CSF eosinophilia, 20 (2.95%) had ≥10/mm3 CSF eosinophilia, and 7 (1.03%) had >16% blood eosinophilia. The patients with ≥10% CSF eosinophilia were significantly younger (p = 0.017), had a lower body temperature (p = 0.036) than patients with ≥10/mm3 CSF eosinophilia among whom bacterial pathogens were detected in 72.2% (13/18) of those who were tested by culture and/or PCR. In contrast, the characteristics of the patients with >16% blood eosinophilia resembled those of patients with ≥10% CSF eosinophilia. We further conducted serological tests and real-time PCR to identify A. cantonensis. Serology or real-time PCR was positive in 3 (42.8%) patients with ≥10% CSF eosinophilia and 6 (85.7%) patients with >16% blood eosinophilia without CSF eosinophils but none of patients with ≥10/mm3 CSF eosinophilia. CONCLUSIONS: The etiology of PM in northern Vietnam is A. cantonensis. The eosinophil percentage is a more reliable predictor of parasitic EM than absolute eosinophil count in the CSF. Patients with PM may present with a high percentage of eosinophils in the peripheral blood but not in the CSF.


Asunto(s)
Angiostrongylus cantonensis/aislamiento & purificación , Eosinofilia/diagnóstico , Meningitis/diagnóstico , Infecciones por Strongylida/diagnóstico , Adulto , Animales , Eosinofilia/sangre , Eosinofilia/parasitología , Femenino , Humanos , Recuento de Leucocitos , Masculino , Meningitis/sangre , Meningitis/parasitología , Persona de Mediana Edad , Infecciones por Strongylida/sangre , Infecciones por Strongylida/parasitología
20.
PLoS One ; 14(9): e0223115, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31553776

RESUMEN

The use of antibiotics in livestock production is considered a major driver of antibiotic resistance on a global scale. In Vietnam, small- and medium-scale livestock producers dominate the domestic market and regulatory pushes have done little to decrease antibiotic use. In order to inform future policy directions, this study aims to explore knowledge, attitudes, and practices amongst livestock producers to identify their perspectives on antibiotic use and resistance. A total of 392 small- and medium-scale producers specialized in pig, poultry and aquaculture production participated in the study. The results showed that the primary reason for antibiotic use reported by producers was for the treatment of infections (69%). However, prophylactic use was also evident, with farmers reporting other reasons for antibiotic use such as "animals display abnormal symptoms or behaviour" (55%), the "weather is about to change" (25%), or "animals on neighboring farms fall ill" (27%). Only one-fifth of producers demonstrated favorable attitudes towards antibiotic use and preventing antibiotic resistance. Moreover, administering antibiotics remained the preferred countermeasure directly applied by farmers at the first indication of disease (17%), compared to enacting hygiene (10%) or quarantine (5%) measures. The results showed divergent trends amongst producers, with pig producers demonstrating higher levels of knowledge, more favorable attitudes, and higher self-reported utilization of good practice. Better knowledge, attitudes, and practices were also associated with producers who engaged in efforts to explore information on antibiotic use and resistance, which improved incrementally with the number of sources consulted and hours invested. However, there were some areas where increased knowledge or more favorable attitude scores did not translate into better practices. For instance, producers with higher levels of formal education performed significantly better than those with lower education in terms of knowledge and attitude, though both groups reported similar practices. The findings of this study may support future interventions to prevent both antibiotic misuse and the development of antimicrobial resistance.


Asunto(s)
Crianza de Animales Domésticos/estadística & datos numéricos , Antibacterianos/uso terapéutico , Acuicultura/estadística & datos numéricos , Infecciones Bacterianas/veterinaria , Agricultores/psicología , Conocimientos, Actitudes y Práctica en Salud , Adulto , Crianza de Animales Domésticos/métodos , Animales , Antibacterianos/farmacología , Acuicultura/métodos , Infecciones Bacterianas/tratamiento farmacológico , Farmacorresistencia Microbiana , Utilización de Medicamentos/estadística & datos numéricos , Escolaridad , Agricultores/estadística & datos numéricos , Femenino , Peces/microbiología , Humanos , Masculino , Persona de Mediana Edad , Aves de Corral/microbiología , Encuestas y Cuestionarios/estadística & datos numéricos , Porcinos/microbiología , Vietnam
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA