The role of chitosan in enhancing the solubility and antibacterial activity of emodin against drug-resistant bacteria.

Similar to most anthraquinone compounds, the pharmacological properties of emodin are limited because of its low water solubility. In this study, the formulation of chitosan and emodin (EMD/CS) was prepared by a bottom-up method with precipitation and sonication steps in order to enhance the solubility of emodin. Thanks to the interactions of oxygen-and nitrogen-containing groups in chitosan with emodin molecules, the solubility of emodin in the formulation was remarkably increased to 0.5 mg/mL. The EMD/CS particles were well dispersed and distributed in a range of sub-micrometer with an average particle size of 342 nm. The EMD/CS formulation exhibited synergic antibacterial activity of emodin and chitosan, against drug-resistant bacterial strains, namely Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli O157:H7 (E. coli O157:H7). When the compositions of emodin and chitosan increased, the antibacterial effectiveness of the EMD/CS formulation increased. The EMD/CS formulation with compositions of 0.5 mg/mL of emodin and 9.0 mg/mL of chitosan could significantly inhibit the proliferation of E. coli O157:H7. Meanwhile, the EMD/CS formulation with a lower concentration of emodin (0.4 mg/mL) and chitosan (7.2 mg/mL) could cause an extermination effect on MRSA. The enhanced solubility of EMD/CS formulation suggests that this formulation can be a potential candidate for the treatment of infectious diseases caused by drug-resistant bacterial pathogens.

Complexes of Ag and ZnO nanoparticles with BBR for enhancement of gastrointestinal antibacterial activity through the impacts of size and composition.

This study introduces the bioformulations of Ag/BBR and ZnO/BBR complexes against pathogenic bacteria in the gastrointestinal tract. Without the use of toxic reduction agents, Ag and ZnO NPs were prepared using an electrochemical method and then facially mixed with BBR solution to form Ag/BBR and ZnO/BBR complexes. BBR molecules are strongly conjugated with Ag and ZnO NPs through coordinated bonding and electrostatic interaction. As a result, the presence of BBR significantly influenced the nanoparticle growth, resulting in the formation of core/shell structured Ag/BBR and ZnO/BBR NPs with small particle sizes. The antibacterial test showed that BBR, Ag, or ZnO components all contributed to the increase of antibacterial ability of Ag/BBR and ZnO/BBR NPs against both methicillin-resistant Staphylococcus aureus (MRSA) and Salmonella enteritidis (S. enteritidis). The bactericidal ability of Ag/BBR and ZnO/BBR complexes against MRSA was exhibited even at a concentration of four-fold dilution (corresponding to 1.25 g L-1 of BBR and 46.25 mg L-1 of Ag) and two-fold dilution (corresponding to 2.5 g L-1 of BBR and 10 mg L-1 of ZnO), respectively, while that of the Ag/BBR complex against S. enteritidis showed at a concentration of two-fold dilution corresponding to 2.5 g L-1 of BBR and 92.5 mg L-1 of Ag. The results obtained in this study support that Ag/BBR and ZnO/BBR complexes can be potential therapeutic agents against gastrointestinal infections.

Elucidating the roles of oxygen functional groups and defect density of electrochemically exfoliated GO on the kinetic parameters towards furazolidone detection.

Using electrochemically exfoliated graphene oxide (GO)-modified screen-printed carbon electrodes for the detection of furazolidone (FZD), a nitrofuran antibiotic, was explored. In this study, we designed some GO samples possessing different oxygen functional group content/defect density by using ultrasonic irradiation or microwave techniques as supporting tools. The difference in physical characteristics of GO led to the remarkable change in kinetic parameters (electron transfer rate constant (k s) and transfer coefficient (α)) of electron transfer reactions at K 3/K 4 probes as well as the FZD analyte. Obtained results reveal that the GO-ultrasonic sample showed the highest electrochemical response toward FZD detection owing to the increase in defect density and number of edges in the GO nanosheets under ultrasonic irradiation. The proposed electrochemical nanosensor enabled the monitoring of FZD in the linear range from 1 µM to 100 µM with an electrochemical sensitivity of 1.03 µA µM-1 cm-2. Tuning suitable electronic structures of GO suggests the potentiality of advanced GO-based electrochemical nanosensor development in food-producing animal safety monitoring applications.

Catastrophic health expenditure in the Northern midlands and mountainous areas and its determinants, Vietnam from 2014 to 2020: a cross-sectional study.

OBJECTIVES: The study assesses households' catastrophic health expenditure (CHE) by income group, urban versus rural area, and influencing factors in the Northern midlands and mountainous areas of Vietnam. DESIGN/SETTING: A cross-sectional study with the four waves of data from 2014, 2016, 2018 and 2020 Vietnam household living standards surveys was used. PARTICIPANTS: The number of participants in this study were 1658, 1661, 1659 and 1662 households in 2014, 2016, 2018 and 2020, respectively. We included households residing in the Northern midlands and mountain areas of Vietnam. OUTCOMES MEASURE: We examined out-of-pocket health payments and capacity to pay by income groups and place of residence, the incidence of CHE and impoverishment. A logistic regression model was used to examine the influence of demographic and socioeconomic characteristics on CHE. RESULTS: The findings showed a remarkable decrease in CHE between 2014 and 2016, followed by a considerable increase between 2016 and 2018. The CHE rates in the region were between 3.5% and 5%, with the highest value observed in 2014. In addition, the differences in household CHE rates according to income and place of residence were observed. The results also indicated that medical impoverishment ranged between 3.4% and 3.9%. Overall, factors such as the burden of disease, rural settlements, increasing use of healthcare services, visiting private health facilities and having an old-aged person in the household were significantly and positively associated with CHE. By contrast, households that were wealthier, participated in health insurance, had a household head employed and female-headed households, were negatively associated with CHE. CONCLUSIONS: The findings provide useful information that can guide policy-makers to design policies, and interventions necessary to reduce CHE in the region, narrow the gap between the rich and the poor, the rural and urban settlements, and ensure universal health coverage.

Antibacterial activity of a berberine nanoformulation.

This study describes the preparation of berberine (BBR) in nanoformulation to enhance its solubility and increase its antibacterial effectiveness against hospital-acquired infections. BBR nanoparticles (BBR NPs) were formed by antisolvent precipitation (ASP) using glycerol as a safe organic solvent. UV-vis absorption spectra demonstrated that the solubility of BBR NPs was greatly enhanced compared to that of pure BBR. Glycerol played a role as a stabilizer for BBR NPs through the formation of hydrogen bonds between glycerol and BBR NPs. The prepared BBR NPs have a narrow size distribution with an average diameter of 156 nm at a concentration of 2.0 mg/mL, measured by dynamic light scattering. After nanoformulation, the concentration of BBR NPs could reach up to 5.0 mg/mL, which is much higher than the saturation concentration without treatment. Results show a strongly enhanced antibacterial activity of BBR NPs compared with that of pure BBR at the same concentration. The minimum bactericidal concentration of BBR NPs against methicillin-resistant Staphylococcus aureus and Escherichia coli O157:H7 was found to be 2.0 and 5.0 mg/mL, respectively. Transmission electron microscopy showed that BBR NPs surrounded the bacterial cells and severely damaged the cell walls. Therefore, BBR NPs prepared by ASP appear to be a potential candidate for the treatment of bacterial pathogens.

Gold nanoparticle-based optical nanosensors for food and health safety monitoring: recent advances and future perspectives.

Modern society has been facing serious health-related problems including food safety, diseases and illness. Hence, it is urgent to develop analysis methods for the detection and control of food contaminants, disease biomarkers and pathogens. As the traditional instrumental methods have several disadvantages, including being time consuming, and having high cost and laborious procedures, optical nanosensors have emerged as promising alternative or complementary approaches to those traditional ones. With the advantages of simple preparation, high surface-to-volume ratio, excellent biocompatibility, and especially, unique optical properties, gold nanoparticles (AuNPs) have been demonstrated as excellent transducers for optical sensing systems. Herein, we provide an overview of the synthesis of AuNPs and their excellent optical properties that are ideal for the development of optical nanosensors based on local surface plasmon resonance (LSPR), colorimetry, fluorescence resonance energy transfer (FRET), and surface-enhanced Raman scattering (SERS) phenomena. We also review the sensing strategies and their mechanisms, as well as summarizing the recent advances in the monitoring of food contaminants, disease biomarkers and pathogens using developed AuNP-based optical nanosensors in the past seven years (2015-now). Furthermore, trends and challenges in the application of these nanosensors in the determination of those analytes are discussed to suggest possible directions for future developments.

A hybrid design of Ag-decorated ZnO on layered nanomaterials (MgAC) with photocatalytic and antibacterial dual-functional abilities.

In this work, Ag@ZnO and Ag@ZnO/MgAC photocatalysts were synthesized using a simple two-step electrochemical method by the addition of magnesium aminoclay (MgAC) as a great stabilizer and a Lewis base, which could donate electrons for reduction of Ag+ and Zn2+ ions, facilitating uniform formation as well as effective inhibition of aggregation of Ag@ZnO nanoparticles (NPs) on the MgAC matrix. Ag@ZnO and Ag@ZnO/MgAC were investigated for photocatalytic degradation of MB and their antibacterial efficiencies. Ag@ZnO/MgAC showed excellent photocatalytic MB degradation with a performance of 98.56% after 80 min of visible-light irradiation and good antibacterial activity against Salmonella (Sal) and Staphylococcus aureus (S. aureus) bacterial strains, providing promising high application potential. Herein, different from the bare ZnO NPs, for Ag@ZnO/MgAC nanocomposites, Ag@ZnO NPs functioned as an effective photocatalyst under visible light illumination, in which, incorporated Ag atoms in the ZnO crystal structure caused the increase in a larger number of lattice defect sites. Benefiting from the strong surface plasmon resonance (SPR) effect of Ag and energy band matching between ZnO and Ag, the visible light absorption capacity and the separation of the photogenerated charge carriers were promoted. Therefore, the MB degradation efficiency of Ag@ZnO/MgAC was considerably accelerated in the presence of produced radicals from visible light illumination.

Determinants of catastrophic health expenditure in Vietnam.

BACKGROUND: The Government of Vietnam has set the goal of achieving universal health coverage (UHC) by 2025. Health insurance (HI) is being considered a tool to achieve this goal. However, out-of-pocket spending and catastrophic health expenditure (CHE) remain high. Research evidence on how to reduce these expenditures to achieve UHC is essential. Therefore, this study examines the determinants of CHE, especially the HI factor. METHOD: To identify HI participation status and other factors associated with CHE, we use logistic regression on a dataset from the 2016 Vietnam Household Living Standards Survey. RESULTS: The study finds that HI is a protective factor against CHE, although this result is not always statistically significant across different subsamples. Moreover, the household head's age and employment status, household size, share of the elderly above 60 years, income, illness status, healthcare utilisation, availability of hospitals, commune health stations with medical doctors and place of residence all correlate with household CHE. CONCLUSION: Although there has been a rise in HI coverage, the financial protection capacity of HI schemes in Vietnam remains inadequate, particularly for households living in rural areas. Further investigations of the causal effect of HI, other health system factors and CHE in rural settings are necessary to reduce the incidence of CHE. Additionally, policies aimed at groups vulnerable to CHE, such as those with higher incidences of severe illness or inpatient admissions, low income, and higher age, should be considered.

Impact of Health Insurance on Health Care Utilisation and Out-of-Pocket Health Expenditure in Vietnam.

BACKGROUND: In recent years, health insurance (HI) has been chosen by many low- and middle-income countries to obtain an important health policy target-universal health coverage. Vietnam has recently introduced the Revised Health Insurance Law, and the effects of the voluntary health insurance (VHI) and heavily subsidised health insurance (HSHI) programmes have not yet been analysed. Therefore, this study is aimed at examining the impact of these HI programmes on the utilisation of health care services and out-of-pocket health expenditure (OOP) in general and across different health care providers in particular. METHODS: Using the two waves of Vietnam Household Living Standard Surveys 2014 and 2016 and the difference-in-difference method, the impacts of VHI and HSHI on health care utilisation and OOP in Vietnam were estimated. RESULTS: For both the VHI and HSHI groups, we found that HI increased the probability of seeking outpatient care, the mean number of outpatient visits, the total number of visits, and the mean number of visits at the district level of health care providers in the last 12 months. However, there was no evidence that the HSHI programmes increased the mean number of inpatient visits and the number of visits at the provincial hospital. We also found that while the VHI programme reduced OOP for both outpatient and inpatient care, the HSHI scheme did not result in a reduction in OOP for hospitalisation, although HI lowered the total OOP. Similarly, we found that for both groups, HI reduced OOP when the insured visited district and provincial hospitals. However, the statistically significant impact was not demonstrated when the enrolees of HSHI programmes visited provincial hospitals. CONCLUSION: The study offers evidence that the Vietnamese HI scheme increased health care service utilisation and decreased OOP for the participants of the VHI and HSHI programmes. Therefore, the government should continue to consider improving the HI system as a strategy to achieve universal health coverage.

Enhanced biomineralization and protein adsorption capacity of 3D chitosan/hydroxyapatite biomimetic scaffolds applied for bone-tissue engineering.

This work presents the enhanced biomineralization and protein adsorption capacity of 3D chitosan/hydroxyapatite (CS/HAp) biomimetic scaffolds synthesized from natural sources applied for bone-tissue engineering (BTE). The scaffolds were prepared by the freeze-drying method, then characterized by X-ray diffraction, scanning electron microscopy, liquid substitution, swelling behavior, and mechanical strength. Fourier transform infrared spectroscopy was also conducted to investigate the interaction between chitosan (CS) and hydroxyapatite (HAp). The biodegradation, biomineralization and protein adsorption capabilities of the scaffolds were evaluated through tests in vitro. Results showed that the 3D CS/HAp scaffolds exhibited highly porous structures with an average pore size of 265 µm, and mean porosity of 75.01%, respectively; the tensile strength of the scaffolds was 2.45 MPa, matching well with that of cancellous bone. The addition of HAp into the CS matrix efficiently decreased the swelling percentage of the CS/HAp scaffolds and retained the suitable degradation rate of the composite scaffolds; the degradation percentage of the CS/HAp scaffolds was 46.37% after 28 days immersed in a physiological solution. The CS/HAp scaffolds demonstrated a higher biomineralization capability than that of the CS scaffolds, releasing a bone-like apatite layer on their surface after 15 days of incubation in simulated body fluids. The presence of HAp mimicking biological apatite in the composite scaffolds facilitated a higher protein adsorption capability, compared to that of the CS scaffolds. The obtained results suggest that the CS/HAp scaffolds have great potential as biocompatible materials for BTE applications.

Spinel ferrite (AFe2O4)-based heterostructured designs for lithium-ion battery, environmental monitoring, and biomedical applications.

The development of spinel ferrite nanomaterial (SFN)-based hybrid architectures has become more popular owing to the fascinating physicochemical properties of SFNs, such as their good electro-optical and catalytic properties, high chemothermal stability, ease of functionalization, and superparamagnetic behaviour. Furthermore, achieving the perfect combination of SFNs and different nanomaterials has promised to open up many unique synergistic effects and advantages. Inspired by the above-mentioned noteworthy properties, numerous and varied applications have been recently developed, such as energy storage in lithium-ion batteries, environmental pollutant monitoring, and, especially, biomedical applications. In this review, recent development efforts relating to SFN-based hybrid designs are described in detail and logically, classified according to 4 major hybrid structures: SFNs/carbonaceous nanomaterials; SFNs/metal-metal oxides; SFNs/MS2; and SFNs/other materials. The underlying advantages of the additional interactions and combinations of effects, compared to the standalone components, and the potential uses have been analyzed and assessed for each hybrid structure in relation to lithium-ion battery, environmental, and biomedical applications.

Tomographic density imaging using modified DF-DBIM approach.

Ultrasonic computed tomography based on back scattering theory is the most powerful and accurate tool in ultrasound based imaging approaches because it is capable of providing quantitative information about the imaged target and detects very small targets. The duple-frequency distorted Born iterative method (DF-DBIM), which uses density information along with sound contrast for imaging, is a promising approach for imaging targets at the level of biological tissues. With two frequencies f1 (low) and f2 (high) through N f 1 and N f 2 iterations respectively, this method is used to estimate target density along with sound contrast. The implications of duple-frequency fusion for the image reconstruction quality of density information along with sound contrast based ultrasound tomography have been analyzed in this paper. In this paper, we concentrate on the selection of parameters that is supposed to be the best to improve the reconstruction quality of ultrasound tomography. When there are restraints imposed on simulated scenarios to have control of the computational cost, the iteration number N f 1 is determined resulting in giving the best performance. The DF-DBIM is only effective if there are a moderate number of iterations, transmitters and receivers. In case that the number of transducers is either too large or too small, a result of reconstruction which is better than that of the single frequency approach is not produced by the implementation of DF-DBIM. A fixed sum N iter of N f 1 and N f 2 was given, the investigation of simulation results shows that the best value of N f 1 is N iter 2 - 1 . The error, when applying this way of choosing the parameters, will be normalized with the reduction of 56.11%, compared to use single frequency as used in the conventional DBIM method. The target density along with sound contrast is used to image targets in this paper. It is a fact that low-frequency offers fine convergence, and high-frequency offers fine spatial resolution. Wherefore, this technique can effectively expand DBIM's applicability to the problem of biological tissue reconstruction. Thanks to the usage of empirical data, this work will be further developed prior to its application in reality.

Deterministic compressive sampling for high-quality image reconstruction of ultrasound tomography.

BACKGROUND: A well-known diagnostic imaging modality, termed ultrasound tomography, was quickly developed for the detection of very small tumors whose sizes are smaller than the wavelength of the incident pressure wave without ionizing radiation, compared to the current gold-standard X-ray mammography. Based on inverse scattering technique, ultrasound tomography uses some material properties such as sound contrast or attenuation to detect small targets. The Distorted Born Iterative Method (DBIM) based on first-order Born approximation is an efficient diffraction tomography approach. One of the challenges for a high quality reconstruction is to obtain many measurements from the number of transmitters and receivers. Given the fact that biomedical images are often sparse, the compressed sensing (CS) technique could be therefore effectively applied to ultrasound tomography by reducing the number of transmitters and receivers, while maintaining a high quality of image reconstruction. METHODS: There are currently several work on CS that dispose randomly distributed locations for the measurement system. However, this random configuration is relatively difficult to implement in practice. Instead of it, we should adopt a methodology that helps determine the locations of measurement devices in a deterministic way. For this, we develop the novel DCS-DBIM algorithm that is highly applicable in practice. Inspired of the exploitation of the deterministic compressed sensing technique (DCS) introduced by the authors few years ago with the image reconstruction process implemented using l 1 regularization. RESULTS: Simulation results of the proposed approach have demonstrated its high performance, with the normalized error approximately 90% reduced, compared to the conventional approach, this new approach can save half of number of measurements and only uses two iterations. Universal image quality index is also evaluated in order to prove the efficiency of the proposed approach. CONCLUSIONS: Numerical simulation results indicate that CS and DCS techniques offer equivalent image reconstruction quality with simpler practical implementation. It would be a very promising approach in practical applications of modern biomedical imaging technology.

Cytotoxicity and antiviral activity of electrochemical - synthesized silver nanoparticles against poliovirus.

Silver nanoparticles (AgNPs) have been proven to have noticeable cytotoxicity in vitro and antiviral activity against some types of enveloped viruses. This paper presents the cytotoxicity and antiviral activity of pure AgNPs synthesized by the electrochemical method, towards cell culture and poliovirus (a non-enveloped virus). Prepared AgNPs were characterized by ultraviolet-visible spectroscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. Before incubation with poliovirus, different concentrations of AgNPs were added to human rhabdomyosarcoma (RD) cell monolayers seeded in 96 well plates for testing their cytotoxicity. The in vitro cytotoxicity and anti-poliovirus activity of AgNPs were daily assessed for cytopathic effect (CPE) through inverted light microscopy. CPE in the tested wells was determined in comparison with those in wells of negative and positive control. Structure analysis showed that AgNPs were formed with a quasi-spherical shape with mean size about 7.1nm and high purity. No CPE of RD cells was seen in wells at the time point of 48h post-incubation with AgNPs at concentration up to 100ppm. The anti-poliovirus activity of AgNPs was determined at 3.13ppm corresponding to the viral concentration of 1TCID50 (Tissue Culture Infective Dose) after 30min, and 10TCID50 after 60min, the cell viability was found up to 98% at 48h post-infection, with no CPE found. Whereas, a strong CPE of RD cells was found at 48h post-infection with the mixture of AgNPs and poliovirus at concentration of 100TCID50, and in wells of positive controls. With mentioned advantages, electrochemical-synthesized AgNPs are promising candidate for advanced biomedical and disinfection applications.

Synthesis, Characterizations of Superparamagnetic Fe3O4-Ag Hybrid Nanoparticles and Their Application for Highly Effective Bacteria Inactivation.

In recent years, outbreaks of infectious diseases caused by pathogenic micro-organisms pose a serious threat to public health. In this work, Fe3O4-Ag hybrid nanoparticles were synthesized by simple chemistry method and these prepared nanoparticles were used to investigate their antibacterial properties and mechanism against methicilline-resistant Staphylococcus aureus (MRSA) pathogen. The formation of dimer-like nanostructure of Fe3O4-Ag hybrid NPs was confirmed by X-ray diffraction and High-resolution Transmission Electron Microscopy. Our biological analysis revealed that the Fe3O4-Ag hybrid NPs showed more noticeable bactericidal activity than that of plain Fe3O4 NPs and Ag-NPs. We suggest that the enhancement in bactericidal activity of Fe3O4-Ag hybrid NPs might be likely from main factors such as: (i) enhanced surface area property of hybrid nanoparticles; (ii) the high catalytic activity of Ag-NPs with good dispersion and aggregation stability due to the iron oxide magnetic carrier, and (iii) large direct physical contacts between the bacterial cell membrane and the hybrid nanoparticles. The superparamagnetic hybrid nanoparticles of iron oxide magnetic nanoparticles decorated with silver nanoparticles can be a potential candidate to effectively treat infectious MRSA pathogen with recyclable capability, targeted bactericidal delivery and minimum release into environment.

Protein A-conjugated iron oxide nanoparticles for separation of Vibrio cholerae from water samples.

Pathogen separation is of great significance for precise detection and prevention of disease outbreaks. For the first time, protein A conjugated with chitosan-coated iron oxide nanoparticles was prepared for pathogen separation at low concentrations from liquid samples. Vibrio cholerae O1 (VO1) bacteria were used for testing the effectiveness of this conjugate. Transmission electron microscopy (TEM) was used to confirm the presence of captured VO1. The results showed that, after binding with a specific antibody, the conjugate allows separation of VO1 bacteria from water samples at a concentration as low as 10 cfu mL(-1). Moreover, the conjugate can be used in parallel with conventional or modern diagnostic tests for quick and accurate detection of pathogens.

Surfactant-assisted size control of hydroxyapatite nanorods for bone tissue engineering.

This study presents the physicochemical characterization of the pluronic surfactant-assisted size control of hydroxyapatite (HAp) nanorods for bone tissue engineering (BTE). Rod-shaped HAp nanoparticles were synthesized via a simple route by hydrothermal treatment and with the assistance of the triblock co-polymer PEO20-PPO70-PEO20 (P123). The films of poly (d, l) lactic acid (PDLLA) were prepared as a substrate to spread synthesized HAp nanorods. Powder X-ray diffraction (XRD), field electron scanning microscopy, Fourier transform infrared spectroscopy, nitrogen adsorption isotherms, and energy-dispersive X-ray spectroscopy were used to characterize the structure and composition of the HAp samples. Results showed that regular rod-shaped HAp nanoparticles (with a mean length of 120 nm and a mean width of 28 nm) were successfully produced. Moreover, synthesized HAp nanorods revealed the rapid formation of bone-like apatite with a distinctive morphology, similar to flower-like apatite; the formation was observed as early as 7 days after incubation in stimulated body fluids. This study is a positive addition to the ongoing research on the preparation of HAp nanostructures toward the development of biocompatible composite scaffolds for BTE applications.

A new nidovirus (NamDinh virus NDiV): Its ultrastructural characterization in the C6/36 mosquito cell line.

We describe the ultrastructure of the NamDinh virus (NDiV), a new member of the order Nidovirales grown in the C6/36 mosquito cell line. Uninfected and NDiV-infected cells were investigated by electron microscopy 24-48 h after infection. The results show that the viral nucleocapsid-like particles form clusters concentrated in the vacuoles, the endoplasmic reticulum, and are scattered in the cytoplasm. Mature virions of NDiV were released as budding particles on the cell surface where viral components appear to lie beneath and along the plasma membrane. Free homogeneous virus particles were obtained by ultracentrifugation on sucrose gradients of culture fluids. The size of the round-shaped particles with a complete internal structure was 80 nm in diameter. This is the first study to provide information on the morphogenesis and ultrastructure of the first insect nidovirus NDiV, a missing evolutionary link in the emergence of the viruses with the largest RNA genomes.

A facile synthesis of nanostructured magnesium oxide particles for enhanced adsorption performance in reactive blue 19 removal.

Magnesium oxide (MgO) has been known as an excellent adsorbent for a variety of the environmentally polluted compounds. This work describes a synthesis of nanostructured MgO particles via a facile procedure by using cetyltrimethylammonium bromide (CTAB). Powder X-ray diffraction, thermal gravimetric, and differential thermal gravimetry (TGA/DTG) analyses were performed to characterize the physical properties of synthesized MgO particles and field emission-scanning electron microscopy (FE-SEM) was used to observe their morphology, whereas nitrogen adsorption-desorption isotherms and Brunauer-Emmett-Teller (BET) method were used to calculate the total surface areas of the samples. The adsorptive performance was studied by batch experiments for reactive blue (RB) 19 dye removal. The results showed that as-prepared MgO particles revealed hexagonal-like shaped platelets with an average diameter in the range of 49-91 nm and a mean thickness of 19-25 nm; meanwhile, MgO CTAB-free particles are aggregated, tiny nanoparticles with an average width of 22 nm and an average length of 77 nm. The maximum adsorption capacity of as-prepared nanostructured MgO for reactive blue (RB) 19 dye was 250 mg g(-1). Furthermore, the correlation between structural characterization (mean size, pore, surface) of the samples and the adsorption performance was also discussed in details.

A novel biosensor based on serum antibody immobilization for rapid detection of viral antigens.

In this paper, we represent a label-free biosensor based on immobilization of serum antibodies for rapid detection of viral antigens. Human serum containing specific antibodies against Japanese encephalitis virus (JEV) was immobilized on a silanized surface of an interdigitated sensor via protein A/glutaraldehyde for electrical detection of JEV antigens. The effective immobilization of serum antibodies on the sensor surface was verified by Fourier transform infrared spectrometry and fluorescence microscopy. The signal of the biosensor obtained by the differential voltage converted from the change into non-Faradic impedance resulting from the specific binding of JEV antigens on the surface of the sensor. The detection analyzed indicates that the detection range of this biosensor is 1-10 µg/ml JEV antigens, with a detection limit of 0.75 µg/ml and that stable signals are measured in about 20 min. This study presents a useful biosensor with a high selectivity for rapid and simple detection of JEV antigens, and it also proposes the biosensor as a future diagnostic tool for rapid and direct detection of viral antigens in clinical samples for preliminary pathogenic screenings in the case of possible outbreaks.