In this work, Pt-SiO2/graphene nanocomposites have been synthesized under solvothermal conditions and investigated as electrocatalysts for methanol oxidation. Structure and morphology of these ...catalysts are characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and nitrogen adsorption/desorption studies. The Pt and SiO2 contents of these nanocomposites are determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Their electrocatalytic properties are investigated by cyclic voltammetry, chronoamperometry, chronopotentiometry and electrochemical impendence spectroscopy. The as-prepared nanocomposites show the improved catalytic performance, better stability and good antiposoining ability compared with Pt supported on graphene catalyst. Particularly, the catalyst containing 9.24% of SiO2 exhibits the best electrocatalytic performance for methanol oxidation with mass activity of 1047mAmg−1.
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•Copper nanowires were patterned directly on flexible substrate by nanosecond laser.•Laser parameters were optimized based on the simulation and experiment results.•Patterned copper ...nanowires electrode turns a traditional smart-window to a transparent display.
Copper nanowire (Cu NW) electrodes have shown promise for use in next-generation transparent conducting films due to their high electrical conductivity, low-cost solution-based synthesis processes, and high transmittance properties. Recently, the use of lasers for the modification of nanostructures has received considerable attention. Despite the advantages of laser machining such as producing any shape in an accurate, time-saving, non-contact process, the laser patterning of Cu NW electrodes has not been extensively studied, particularly the heat effect of the laser irradiation process on the flexible substrate. In this report, we present experimental and computational results of a selective and direct patterning process by using nanosecond pulsed laser irradiation. The experimental and simulation results were used to optimize the laser ablation parameters for the patterning process of the ultra-long Cu NW transparent electrodes so as to not damage the flexible substrates. Finally, a bifunctional flexible smart-window was fabricated to demonstrate a practical application of the laser-patterned Cu NW electrodes.
This research presents a development of the dynamical model for ballasted railway tracks by combining two models: a periodically supported beam model for the rail and model of beam posed on a ...viscoelastic foundation for the sleeper. In this development, two beam theories can be used to describe the dynamic behavior of beam: Euler–Bernoulli and Timoshenko. In steady-state condition, a relation between the reaction force applied on the support and displacement of rail is established in the frequency domain. In the other way, these two variables are linked with the help of Green’s function for the sleeper. By performing the two previous analyses, the dynamic responses of rails are obtained analytically in the frequency domain. The numerical examples show the influence of beam models for the rails and sleeper on the dynamic responses. This work provides analytical choices to calculate the dynamic track responses where the rails and sleeper can be described by the two beam theories.
One novel chromanone acid derivative, namely inocalophylline C (1), together with one known compound calophyllolide (2), were isolated from the methanolic extract of nut oil resin of Calophyllum ...inophyllum L., a medicinal plant widely distributed in Vietnam. The isolated compound structures were elucidated by spectroscopic methods and the absolute configuration of 1 was established by the single-crystal X-ray crystallography as ethyl (R) 3-((2 R,3R,6R)-4-hydroxy-2,3-dimethyl-6-((R)-5-methyl-2-(prop-1-en-2-yl)hex-4-en-1-yl)-6-(3-methylbut-2-en-1-yl)-5,7-dioxo-3,5,6,7-tetrahydro-2H-chromen-8-yl)-3-phenylpropanoate.
Early neurological deterioration (END) is progressive neurological deterioration with an increase in NIHSS score of 2 points or more in the first 72 hours from the onset of acute ischemic stroke. END ...increases the risk of poor clinical outcomes at day 90 of ischemic stroke. We will study the frequency, predictors, and outcomes of patients with END in a case-control study at a comprehensive stroke centre in Vietnam. of the design is a descriptive observational study, longitudinal follow-up of patients with minor stroke hospitalized at the Stroke Center of Bach Mai Hospital from December 1, 2023, to December 1, 2024. Minor stroke patients characterized by NIHSS score ≤ 5 hospitalized within 24 hours of symptom onset will be recruited. The estimated END rate is about 30%, relative accuracy ε = 0.11, 95% reliability, expected 5% of patients lost data or follow-up, and an estimated sample size of 779 patients. This study will help determine the END rate in patients with minor stroke and related factors, thereby building a prognostic model for END. Our study determined the END rate in patients with minor stroke in Vietnam and also proposed risk factors for minor stroke management and treatment.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Aims
Anthrax is reported with frequency but poorly understood in Southeast Asian countries including Vietnam. In Vietnam, anthrax surveillance is national. However, case detection, prevention, and ...control are implemented locally at the provincial level. Here, we describe the epidemiological characteristics, identify spatial clusters of human anthrax, and compare the variation in livestock anthrax vaccine coverage to disease incidence in humans and livestock using historical data in Son La province, Vietnam (2003–2020).
Methods and Results
Most human cases occurred between April and September. Most of the patients were male, aged 15–54 years old. The human cases were mainly reported by public district hospitals. There was a delay between disease onset and hospitalization of ~5 days. We identified spatial clusters of high–high incidence communes in the northern communes of the province using the local Moran's I statistic. The vaccine coverage sharply decreased across the study period. The province reported sporadic human anthrax outbreaks, while animal cases were only reported in 2005 and 2022.
Conclusions
These results suggest underreporting for human and livestock anthrax in the province. Intersectoral information sharing is needed to aid livestock vaccination planning, which currently relies on reported livestock cases. The spatial clusters identify areas for targeted surveillance and livestock vaccination, while the seasonal case data suggest prioritizing vaccination campaigns for February or early March ahead of the April peak. A regional approach for studying the role of livestock trading between Son La and neighbouring provinces in anthrax occurrence is recommended.
Abstract
Background
High-resolution anorectal manometry (HRAM) has been developed to improve measurement of anorectal functions. This study aims to identify normal HRAM values in healthy young ...Vietnamese adults.
Methods
We conducted a cross-sectional study at the National Hospital of Traditional Medicine (Hanoi, Vietnam) from July through December 2014. Healthy young adults were invited to participate in the study. All anorectal measurement values were performed using the ISOLAB high-resolution manometry system. Differences between groups were analyzed using Student’s t-tests.
Results
Thirty healthy young adults, including 15 males and 15 females aged 19–26 years, were recruited. Mean functional anal canal length was 3.4 ± 0.5 cm (range: 2.4–4.8 mm). Mean maximum resting pressure, mean maximum squeezing pressure, mean maximum coughing pressure, and mean maximum strain pressure were 65.5, 168.0, 125.9, and 84.2 mm Hg, respectively. All anal pressure values were significantly different between males and females. For rectal sensation measurements, only the volume at first sensation was significantly higher in males than in females.
Conclusions
This study provides normal HRAM value for healthy young adults in Vietnam. Sex may influence anal pressure and first rectal sensation values in this cohort. Further studies should be conducted in order to improve the quality of HRAM normal values and to confirm the effects of sex.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Introduction
Doppler-guided transanal hemorrhoidal dearterialization (THD) was considered a less invasive and innovative method to treat hemorrhoidal disease, but it may impact the anal area during ...dearterialization and mucopexy. Thus, this study aimed to assess any changes in anorectal manometry of grade III and IV hemorrhoidal patients following THD treatment.
Methods
This prospective observational study was conducted with patients who had grades III and IV hemorrhoidal disease. The patients were treated using THD at the Department of Surgery in the National Hospital of Traditional Medicine (Hanoi, Vietnam) between June 2012 and December 2013. Anorectal manometry was performed prior to THD and again between 6 and 12 months following the procedure.
Results
A total of 40 patients were enrolled in the study, including 32 with grade III hemorrhoids and 8 with grade IV hemorrhoids. The proportion of male patients (65%) was higher than that of female patients (35%), and the majority of patients (82.5%) were > 40 years old. The mean duration of symptoms prior to treatment was 12.3 years. The mean length of the anal sphincter was unchanged before and after THD (3.64 ± 0.40 cm prior to treatment vs. 3.66 ± 0.48 cm following treatment;
p
= 0.57). Significant differences in treatment-related changes were detected for all anorectal manometric measurements except maximum squeezing pressure (
p
< 0.05). No patient showed anal stenosis or fecal incontinence.
Conclusion
The THD technique did not change the length of the anal sphincter 6 months after hemorrhoid treatment. The values of anal pressure and rectal sensation decreased almost significantly between treatment and the follow-up visit. We suggest that further studies, which include larger sample sizes, should be conducted to confirm THD effectiveness in terms of anorectal functions.
•Performance of Savonius rotor is improved using the FX74-CL5-140 airfoil-shaped blade.•The impact of a natural airfoil-shaped blade is demonstrated by the CFD approach.•The fluid flow ...characteristics are explored with POD model analysis.•Up to 8.7% and 16.5% enhancement in Cp was observed for different overlap ratios.
The present study introduces a novel rotor configuration with an airfoil-shaped blade, based on the low-speed high-lift FX74-CL5-140 airfoil, for enhancing the performance of the Savonius wind turbine for a practical application in urban areas. The preferment of the present design over the original one with a semicircular shape is confirmed by the sequence of unsteady two-dimensional (2D) numerical simulation. The results demonstrate a new power coefficient peak (up to 16.5 % better than that of the original rotor) could be gained at the tip speed ratio (TSR) of 1.1. The effective working range is further extended to TSR > 0.7 compared to that at TSR > 1.0 in the literature. Insight into the flow dynamic, including pressure, velocity, streamline, and wake analysis, reveals that the thick blade near the overlap region, benefiting in terms of the turbine’s high performance. The airfoil blade increases the momentum energy around the rotor, changes the pressure on the concave side, and varies the origin of the pressure force, leading to an increase in the moment arm with more torque exhibited on the rotor at high TSR. In addition, the proper orthogonal decomposition (POD) analysis is also performed to better understand the flow phenomena behind the rotor. Overall, the present design is beneficial for urban applications because it can enhance the rotor performance without losing the omnidirectional and compactness features.
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