Search

Tuberculosis is still burden in developing countries, including Viet Nam. Molecular techniques such as PCR, Real-time PCR play an important role in tuberculosis diagnostics. Specimens for tuberculosis testing are complex such as sputums, gastric fluids. DNA extraction are commonly performed by commercial kits, with little study about efficacy for tuberculosis testing assays. This study describes efficacy of three kits G-Spin (Intron-Korea), RIBO- sorb (Amplisens-Russia), DNA/RNA Prep (Sacace-Italy), and Salting-out method using basic reagents. Samples were 15 sputums collected from tuberculosis infected cases. As the result, recovered ADN was highest in DNA/RNA Prep, folowed by Salting-out, G-Spin, and last by RIBO - sorb. Oder of purification value was RIBO - sorb, G-Spin, Salting-out, and DNA/RNA Prep. About PCR for 16S gene, 15/15 samples were succeed in G-Spin and DNA/RNA Prep, 14/15 from RIBO-prep, 13/15 from Salting-out. Real-time PCR Mycobacterium tuberculosis (Sacace-Italy) detected 14/15 samples from G-Spin, DNA/RNA Prep, and RIBO-sorb, but Salting-out detected 13/15 samples. Therefore, G-Spin and DNA/RNA Prep show higher efficacy in amplication of 16S gene and Real-time PCR assays for tuberculosis. RIBO- sorb has equal efficacy in Realtime PCR, but more priority in purification. Salting-out perform equally in recovery and purification with commercial kits, but limited in efficacy of Mycobacteria genome amplification.

In recent years, the burden of nontuberculous mycobacteria pulmonary disease has increased worldwide. Nontuberculous mycobacteria - NTM infection is often misdiagnosed with Mycobacterium tuberculosis - MTB because of their similar clinical manifestations and preclinical manifestations. For MTB, the National Tuberculosis Program and the Ministry of Health (Vietnam) have a standard treatment regimen, while for NTM, an individualized treatment regimen based on infectious NTM species. Therefore, accurate identification of the causative NTM species can help clinicians choosing an effective treatment regimen. Among 122 suspected NTM samples collected at National Hospital 74, we successfully identified 115 strains belonging to NTM. Analytical DNA sequences, building phylogenetic trees were analyzed by Bioedit, ClustalX2, and MEGA-X software; comparing and identifying reference species from gene bank were used BLAST-NCBI. Slow-growing mycobacteria accounted for 61.7%, consists of Mycobacterium avium complex (37.4%), Mycobacterium lentiflavum (7.0%), Mycobacterium simiae (7.0%), Mycobacterium gordonae complex (5.2%) and other species less than 2.0%. The detection rate of rapid-growing mycobacteria was 38.3% including Mycobacterium abscessus complex (31.3%), and Mycobacterium fortuitum (7.0%). The most prevalent NTM species belonged to Mycobacterium avium complex and Mycobacterium abscessus complex (68.7%). The proportion of NTM infection in patients 50 years and older is 2.3 times higher than in patients under 50 years. This proportion is 5 times higher in females while there is no significant difference in males.

Rickettsiosis is a zoonotic disease caused by Rickettsiae which are gram negative bacteria, obligate intracellular. These pathogens are transmitted to human through infected ticks, mites, fleas, lice, louse… In this study, The 17kDa and OmpA partial genes of Rickettsia were amplified to detect Rickettsial DNA in buffalo ticks and louse (Haematopinus tuberculatus) collected in Ha Giang province. The PCR products were sequenced, analyzed and build phylogenetic tree by Bioedit, Mega-X softwares; were compared and identified the reference strain sequences by BLAST- NCBI, USA. The results indicated that 14/25 tick samples and 2/14 louse samples were positive for Rickettsia SFG by PCR. Sequence analysis of OmpA gen showed that 14 clone isolated from the tick samples exhibites a 98% - 100% similarity to Rickettsia japonica, whereas 2 clone isolated from the louse samples were 98% similar to Rickettsia massiliae. Thus, our research showed that Rickettsia SFG including Rickettsia japonica and Rickettsia massiliae were detected in ticks and louse, respectively collected in Ha Giang province, Vietnam.

The Seq2Seq model and its variants (ConvSeq2Seq and Transformer) emerge as a promising novel solution to the machine translation problem. However, these models only focus on exploiting knowledge from bilingual sentences without paying much attention to utilizing external linguistic knowledge sources such as semantic representations. Not only do semantic representations can help preserve meaning but they also minimize the data sparsity problem. However, to date, semantic information remains rarely integrated into machine translation models. In this study, we examine the effect of abstract meaning representation (AMR) semantic graphs in different machine translation models. Experimental results on the IWSLT15 English-Vietnamese dataset have proven the efficiency of the proposed model, expanding the use of external language knowledge sources to significantly improve the performance of machine translation models, especially in the application of low-resource language pairs.

In this paper we provide an upper bound for the conjunction probability of independent Gaussian smooth processes, and then, we prove that this bound is a good approximation with exponentially smaller error. Our result confirms the heuristic approximation by Euler characteristic method of Worsley and Friston and also implies the exact value of generalized Pickands constant in a special case. Some results for conjunction probability of correlated processes are also discussed.

We combined advanced TEM (HRTEM, HAADF, EELS) with solid-state (SS)MAS NMR and electroanalytical techniques (GITT, etc.) to understand the site-specific sodiation of selenium (Se) encapsulated in a nanoporous carbon host. The architecture employed is representative of a wide number of electrochemically stable and rate-capable Se-based sodium metal battery (SMB) cathodes. SSNMR demonstrates that during the first sodiation, the Se chains are progressively cut to form an amorphous mixture of polyselenides of varying lengths, with no evidence for discrete phase transitions during sodiation. It also shows that Se nearest the carbon pore surface is sodiated first, leading to the formation of a core-shell compositional profile. HRTEM indicates that the vast majority of the pore-confined Se is amorphous, with the only localized presence of nanocrystalline equilibrium Na

Background A bisresorcinol was isolated as the main constituent of Heliciopsis terminalis’s trunk (Proteaceae). Recently, resorcinol is applied as an active whitening agent in various cosmetic products. Because of the structural mimic to resorcinol, benefits of the bisresorcinol as an aging-enzyme antagonist were demonstrated in this study. Methods The bisresorcinol was purified from the crude ethanolic extract of H. terminalis’s trunk by solvent extraction and preparative chromatography, respectively. Inhibitory activity on collagenase, elastase, and tyrosinase of the compound was investigated by using a different spectroscopic technique. Molecular docking was carried out to predict possible interactions of the substance around the enzyme active sites. Results The IC50 values on collagenase of the bisresorcinol and caffeic acid were 156.7 ± 0.7 and 308.9 ± 1.6 µmole L−1, respectively. For elastase activity, the IC50 of 33.2 ± 0.5 and 34.3 ± 0.3 µmole L−1 was respectively determined for the bisresorcinol and ursolic acid. The bisresorcinol was inhibitory to tyrosinase by exhibiting the IC50 of 22.8 µmole L−1, and that of 78.4 µmole L−1 was present for β-arbutin. The bisresorcinol bound to collagenase, elastase, and tyrosinase with the respective binding energies of −5.89, −5.69, and −6.57 kcal mol−1. These binding energies were in the same ranges of tested inhibitors. The aromatic phenol groups in the structure were responsible for principle as well as supporting binding interactions with enzymes. Hydrogen binding due to hydroxyl groups and π-related attractive forces from an aromatic ring(s) provided binding versatility to bisresorcinol. Conclusion The bisresorcinol purified from H. terminalis might be useful for inclusion in cosmetic products as an aging-enzyme antagonist.

In this paper, we obtain an asymptotic formula for the persistence probability in the positive real line of a random polynomial arising from evolutionary game theory. It corresponds to the probability that a multi-player two-strategy random evolutionary game has no internal equilibria. The key ingredient is to approximate the sequence of random polynomials indexed by their degrees by an appropriate centered stationary Gaussian process., revised version

We report a bifunctional sodium metal battery (SMB) and lithium metal battery (LMB) cathode based on 63 wt.%SeS covalently bonded to a co-pyrolyzed polyacrylonitrile (PAN) host, termed “SeSPAN”. This dense, low surface area, fully-amorphous electrode offers a highly favorable combination of reversible capacity, rate capability, and cycling life: At a fast charging rate of 1 A g−1, the reversible capacities with Na and Li are 632 and 749 mAh g−1 (based on active SeS), with cycle 1 CE of 81% in both cases. At an ultra-fast charging rate of 4 A g−1 (∼5C) the reversible capacities with Na and Li are 453 and 604 mAh g−1. Li-SeSPAN degrades 3% at cycle 500, while with Na-SeSPAN degrades by 17% after 150 cycles at 0.5 A g−1. Both Na and Li cells display a uniquely low voltage hysteresis (210 and 200 mV at a current density of 0.2 A g−1), indicative of facile charge-discharge kinetics. Analysis of the post-cycled anodes shows negligible S or Se crossover, with neither species being detected in the Li-SEI after extended cycling.

In this paper, we obtain the persistence exponents of random Weyl polynomials in both cases: the nonnegative axis and the whole real axis. Our result confirms the predictions given by Schehr and Majumdar (J Stat Phys 132(2):235–273, 2008). In the nonnegative axis case, Dembo and Mukherjee (Ann Probab 43(1):85–118, 2015) gave an upper bound for the persistence exponent by considering the persistence probability on a suitable interval. Our main contribution is to prove this upper bound is the exact exponent and to extend to the whole real axis case.

2D ultrathin nanomaterials have attracted a significant interest for their application in flexible and lightweight energy storage devices. In this work, we report the fabrication, by electrophoretic deposition (EPD), of flexible all-solid-state symmetric high cell potential supercapacitors, comprised of holey reduced graphene oxide – manganese dioxide nanosheets (HGM). HGM films were electrophoretically deposited in a layer-by-layer fashion onto targeted substrates, with net thicknesses ranging from 0.2 to 2.5 μm. The assembled HGM films were highly compact with the density of ∼2.2 g cm−3. The resulting symmetric HGM supercapacitors, using PVA-LiClO4 gel as an electrolyte, exhibited excellent electrochemical capacitive performance over a wide cell potential window of 0.0–1.6 V. Operating at ultra-high charge-discharge rates, up to 5000 mV s−1, the HGM supercapacitors delivered excellent areal specific capacitances of 12–46 mF cm−2, corresponding to volumetric specific capacitances of 557–182 F cm−3 at thickness of 0.2–2.5 μm, respectively. Furthermore, the HGM supercapacitors exhibited long-term cycling stability with a retention over 80% of its initial capacitance after 2000 cycles. Considering the facile scale-up capability of the EPD process, our approach paves a promising route for the manufacture of next-generation flexible all-solid-state supercapacitors with high energy and high power density.

Hydrogenated TiO2 has recently attracted considerable attention as potential electrode materials for supercapacitors due to its abundance, low cost, high conductivity, remarkable rate capability, and outstanding long-term cycling stability. Herein, we demonstrate the synthesis of hydrogenated TiO2 nanoparticles anchored on reduced graphene oxide nanosheets (HTG) in the form of sandwich-like nanosheet composites. Further, we explored their implementation as electrode materials for high voltage, symmetric supercapacitors, operating in the voltage window of 0–1.8 V. The HTGs were prepared by a sol-gel method, followed by hydrogenation in the temperature range 300–500 °C. Of the prepared composites, HTG prepared at 400 °C exhibited the largest specific capacitance of 51 F g−1 at the current density of 1.0 A g−1 and excellent rate capability with 82.5% capacitance retention as the current density increased 40-fold, from 0.5 to 20.0 A g−1. HTG's excellent rate capability was attributed to its sandwich-like nanostructure, in which ultrasmall hydrogenated TiO2 nanoparticles densely anchored onto both surfaces of the two-dimensional reduced graphene oxide sheets. Moreover, HTG-based supercapacitors also exhibited long-term cycling stability with the retention over 80% of its initial capacitance after 10,000 cycles. These properties suggest that HTG is a promising electrode material for the scalable manufacture of high-performance supercapacitors.

Using a large proprietary database of transaction-level institutional trades for the 1997–2011 period, we find that institutional investors are net sellers in dividend reduction firms during the two quarters prior to the announcements. They also trade more intensively in firms that do not prepare the market for dividend cuts or that have greater information asymmetry. Trading by both pension plan sponsors and money managers affects the market's reaction to the dividend reduction announcements. Finally, all institutional investors earn significant profits by trading in the two quarters prior to the announcements, and money managers outperform pension plan sponsors.

Over the past decades, Vietnam has made great strides in reducing the rate of mortality in HIV-related deaths, due to increased access of antiretroviral therapy (ART); however, given the significantly high level of treatment failure (TF), it is essential to identify markers that describe the failure of ART in HIV-1 infected children. A nested case–control study was conducted with clinical data collected from 101 HIV-infected children [26 TF and 75 treatment success (TS)] at National Hospital of Pediatrics, Vietnam (2008–2012). The results showed that certain factors including height, weight, vaccination with Hepatitis B, and platelet were significantly different between TF and TS before starting the treatment. In addition, age to start the treatment, CD4 percentage, and opportunistic infection were found to significantly predict treatment outcome most frequently, implying the importance of clinical markers in the treatment response by Cox regression analysis. There is an inherent complexity within clinical markers that is challenging to determine HIV-pediatric failure and further research is needed to build a complete picture to guide clinical, evidence-based practice.

Assessing diagnostic efficacy of shig/eiec-salm-camp-f1 (Amplisens) Kit in direction of three bacteria causing cute diarrhea (Campylobacter, Salmonella and Shigella). 96 feces specimens were collected from non-treated pediatric patients with acute diarrhea and 30 controls were collected from normal persons without gastrointestinal disease. The sensitivity and specificity of Amplisen Shig/EIEC-salm-camp-F1 kit (Interlab Servive Company, Russian Federation) were evaluated by using real-time PCR technique. The results showed that Amplisens kit had the high specificity (100%) and high sensitivity (100%). The detection limit was at least 103 CFU/mL. These results were similar to the those of the Sacace kit (standard kit) that has been commercialized in Vietnam. The results also showed that 17.71%, 11.46%, and 7.29 % of the specimens were positive for Campylobacter, Salmonella and Shigella, respectively, in which 1 sample was detected the co-infection of Campylobacter and Salmonella (1.04%). Therefore, the Amplisens kit can be valuable in early diagnosis of acute infectious diarrhea caused by three bacteria including Campylobacter, Shigella, Salmonella in Vietnam.

We show that Venture Capital (VC)-backed targets receive a significantly higher fraction of stock and a greater likelihood of all-stock offers than non-VC-backed targets, even after controlling for self-selection bias, differences between VC-backed and non-VC-backed targets, and VC information bridge-building. Additionally, VC-backed targets receive a larger fraction of stock when the acquirer is young and risky, and has high growth rate, large investment and potential managerial improvement. Independent VCs, reputable VCs and VC syndicates who are capable of monitoring and advising accept a larger proportion of stock. We also document that the acquirer’s short-term and long-term returns are more positive when VC-backed targets choose stock payment. Altogether, our results indicate that VCs strategically hold shares of acquirers who meet their investment preferences and contribute to their performance.

Linh Vu Phuong Dang,1 Viet Hung Pham,2 Duc Minh Nguyen,3 Thanh Thi Dinh,1 Thu Hoai Nguyen,4 Thanh Hai Le,5 Van Lam Nguyen,6 Thi Phuong Vu7,8 1Public Health Laboratory, Hanoi University of Public Health, Hanoi, Vietnam; 2Department of Microbiology, Vietnam National Hospital of Pediatrics, Hanoi, Vietnam; 3Department of Geriatrics, National Hospital of Acupuncture, Hanoi, Vietnam; 4Department of Training and Direction Activity, National Geriatric Hospital, Hanoi, Vietnam; 5Department of Emergency, Vietnam National Hospital of Pediatrics, Hanoi, Vietnam; 6Department of Infectious Disease, Vietnam National Hospital of Pediatrics, Hanoi, Vietnam; 7Department of Biochemistry, Hanoi Medical University, Hanoi, Vietnam; 8Department of Biochemistry, Dinh Tien Hoang Institute of Medicine, Hanoi, Vietnam Background: HIV-infected children suffer from higher levels of treatment failure compared to adults. Immunoactivation, including humoral immunoactivation reflected by increased immunoglobulin levels, is believed to occur early during HIV infection. Therefore, we wanted investigate alteration in immunoglobulin levels in association with treatment response in HIV-infected children. Methods: A nested case–control study was conducted using clinical data collected from 68 HIV-infected children enrolled at the National Hospital of Pediatrics, Vietnam. Results: The results showed that immunoglobulin levels, CD4 T-cell counts, CD4 T-cell percentage, and HIV load were significantly higher in the treatment-failure group than the treatment-success group at treatment initiation. IgG and IgA levels were negatively correlated with CD4 T-cell counts (P=0.049 and P

Ruthenium oxide (RuO2) nanomaterials exist as excellent materials for electrochemical capacitors. However, they tend to suffer from low mechanical flexibility when cast into films, which makes them unsuitable for flexible device applications. Herein, we report an environmentally friendly and solution-processable approach to fabricate RuO2-based composite electrodes for flexible solid state supercapacitors. The composites were produced by anchoring RuO2 nanoparticles onto holey reduced graphene oxide (HRGO) via a sol-gel method, followed by the electrophoretic deposition (EPD) of the material into thin films. The uniform anchoring of ultra-small RuO2 nanoparticles on the two-dimensional HRGO sheets resulted in HRGO-RuO2 hybrid sheets with excellent mechanical flexibility of HRGO. EPD induced a layer-by-layer assembly mechanism for the HRGO-RuO2 hybrid sheets, which resulted in a binder-free, flexible electrode. The obtained HRGO-RuO2 flexible supercapacitors exhibited excellent electrochemical capacitive performance in a PVA-H2SO4 gel electrolyte with a specific capacitance of 418 F g−1 and superior cycling stability of 88.5% capacitance retention after 10,000 cycles. In addition, these supercapacitors exhibited high rate performance with capacitance retention of 85% by increasing the current density from 1.0 to 20.0 A g−1, and excellent mechanical flexibility with only 4.9% decay in the performance when bent 180°.

We report on the formation of Pt nanoparticle monolayers by electrophoretic deposition from nonpolar solvents. First, the growth kinetics of Pt nanoparticles prepared by the reverse micelle technique are described in detail. Second, a model of nanoparticle charging in nonpolar media is discussed and methods to control the nanoparticle charging are proposed. Finally, essential parameters of the electrophoretic deposition process to control the deposition of nanoparticle monolayers are discussed and mechanisms of their formation are analyzed.

Graphene hydrogels have been considered as ideal materials for high-performance supercapacitors. However, their low volumetric capacitance significantly limits its real application. In this study, we report an environment-friendly and scalable method to prepare high packing density, electrochemically reduced graphene oxide hydrogels (ERGO) for supercapacitor application by the electrophoretic deposition of graphene oxide onto nickel foam, followed by the electrochemical reduction and hydraulic compression of the deposited materials. The as-prepared ERGO on nickel foam was hydraulic compressed up to 20 tons, resulting in an increase of the packing density of ERGO from 0.0098 to 1.32 g cm–3. Consequently, the volumetric capacitance and volumetric energy density of ERGOs greatly increased from 1.58 F cm–3 and 0.053 Wh cm–3 (as-prepared ERGO) to 176.5 F cm–3 and 6.02 Wh cm–3 (ERGO compressed at 20 tons), respectively. The ERGOs also exhibited long-term electrochemical stability with a capacitance retention in...

BACKGROUND There are currently two markers used to monitor treatment response to anti-retroviral therapy (ART) in HIV-infected children: CD4 T-cell count and HIV viral load; but analysis of these could be challenging in resource-poor countries. The aim of this study was therefore to determine whether change in growth parameters such as weight-for-age Z score (WAZ), height-for-age Z score (HAZ) and body mass index-for-age Z score (BMIZ) is associated with treatment response in HIV-infected children. METHODS This was a nested case-control study, in which the data were collected at enrolment and then periodically every 6 months for a total 36 month follow up of 107 HIV-infected children enrolled and treated at National Hospital of Pediatrics, Vietnam. RESULTS At treatment initiation, WAZ, HAZ and BMIZ were not significantly higher in the treatment success (TS) group compared with the treatment failure (TF) group. After ART initiation, WAZ and HAZ increased, and this was significant in the TS group (from -1.5 to -0.54, P

Mesoscale crumpled graphene oxide roses (GO roses) were synthesized by using colloidal graphene oxide (GO) variants as precursors for a hybrid emulsification/rapid evaporation approach. This process produced rose-like, spherical, reduced mesostructures of colloidal graphene oxide, with corrugated surfaces and particle sizes ranging from ~800 nm to 15 μm. The morphology and chemical structure of these produced GO roses was investigated using electron microscopy and spectroscopy techniques. The proposed synthesis route provides control over particle size, morphology and chemical properties of the synthesized GO roses.

We report on the electrophoretic deposition (EPD) of metal nanoparticles (NPs) prepared in reverse micelles on semiconductor substrates with the aim to fabricate sensitive Schottky-based hydrogen sensors with fast response and high degree of selectivity. We discuss the mechanism of NP monolayer formation and show which parameters are essential for the transition from three-dimensional to two-dimensional growth.

Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

Adhesion between film and substrate is critical for electronic device and coating applications. Interfacial development between electrophoretically deposited graphene oxide films on Al 1100 and Al 5052 alloys were investigated using FT-IR and XPS depth profiling techniques. Obtained results suggest metal ion permeation from the substrates into deposited graphene oxide films. The interface between the films and the substrates were primarily composed of Al-O-C bonds from oxygenated defects on graphene oxide plane rather than expected Al-C formation. Films heat treated at 150 °C had change in microstructure and peak shifts in XPS spectra suggesting change in chemical structure of bonds between the films and the substrates.

Herein, we report a facile, low cost, and environmentally friendly approach to prepare reduced graphene oxide–ruthenium oxide hybrid (RGO–RuO2) materials for supercapacitor electrode applications by in situ sol–gel deposition of RuO2 nanoparticles on the surface of graphene oxide (GO), followed by a reduction of GO in a strong alkaline medium at a low temperature. The combination of the sol–gel route and the reduction of graphene oxide at low temperatures resulted in ultrafine, hydrated amorphous RuO2 particles with sizes of only 1.0–2.0 nm, which uniformly decorated the surfaces of RGO sheets. The obtained RGO–RuO2 supercapacitor exhibited excellent electrochemical capacitive performance in a 1 M H2SO4 electrolyte with a specific capacitance more than 500 F g−1 at a current density of 1.0 A g−1 and high rate performance with the capacitance retention of 86% when the current density was increased 20 times, from 1.0 to 20.0 A g−1 in a two-electrode test cell configuration. The RGO–RuO2 system also showed good cycling stability with a capacitance retention of 87% after 2000 cycles. The excellent capacitive properties of RGO–RuO2 could be attributed to the uniform anchoring of ultra-small, hydrated amorphous RuO2 nanoparticles on the surface of RGO sheets, resulting in synergistic effects between them. The developed approach represents an exciting direction for enhancing the device performance of the graphene–metal oxide composite supercapacitors and can be used for designing the next generation of energy storage devices.

In this paper we study the moderate deviations for the magnetization of critical Curie-Weiss model. Chen, Fang and Shao considered a similar problem for non-critical model by using Stein method. By direct and simple arguments based on Laplace method, we provide an explicit formula of the error and deduce a Cram\'er-type result., Comment: 12 pages, accepted for publication in Electronic Communication in Probability

Using a large proprietary database of transaction-level institutional trades for the period from 1997-2011, we find that institutional investors are net sellers in dividend reduction firms during the two quarters prior to the announcements. They also trade more intensively in firms that do not prepare the market for dividend cuts or that have greater information asymmetry. Trading by both pension plan sponsors and money managers affects the market reaction to the announcements. Finally, all institutional investors earn positive profits by trading in the two quarters prior to the announcements, and money managers outperform pension plan sponsors.