Background One hundred days after SARS-CoV-2 was first reported in Vietnam on January 23rd, 270 cases were confirmed, with no deaths. We describe the control measures used by the Government and their relationship with imported and domestically-acquired case numbers, with the aim of identifying the measures associated with successful SARS-CoV-2 control. Methods Clinical and demographic data on the first 270 SARS-CoV-2 infected cases and the timing and nature of Government control measures, including numbers of tests and quarantined individuals, were analysed. Apple and Google mobility data provided proxies for population movement. Serial intervals were calculated from 33 infector-infectee pairs and used to estimate the proportion of pre-symptomatic transmission events and time-varying reproduction numbers. Results A national lockdown was implemented between April 1st and 22nd. Around 200 000 people were quarantined and 266 122 RT-PCR tests conducted. Population mobility decreased progressively before lockdown. 60% (163/270) of cases were imported; 43% (89/208) of resolved infections remained asymptomatic for the duration of infection. The serial interval was 3·24 days, and 27·5% (95% confidence interval, 15·7%-40·0%) of transmissions occurred pre-symptomatically. Limited transmission amounted to a maximum reproduction number of 1·15 (95% confidence interval, 0·37-2·36). No community transmission has been detected since April 15th. Conclusions Vietnam has controlled SARS-CoV-2 spread through the early introduction of mass communication, meticulous contact-tracing with strict quarantine, and international travel restrictions. The value of these interventions is supported by the high proportion of asymptomatic and imported cases, and evidence for substantial pre-symptomatic transmission.

Purpose: The purpose of this study was to evaluate the safety and efficacy of mechanical thrombectomy with a direct aspiration first-pass technique (ADAPT) using large-bore catheters in patients with acute ischemic stroke due to large vessel occlusion (LVO) in a hospital in Vietnam. Methods: This was a retrospective review of patients with acute ischemic stroke due to LVO who were diagnosed and underwent mechanical thrombectomy using ADAPT with large-bore catheters at Bach Mai Hospital from January 2017 to June 2018. Results: Seventy-three patients (47.9% female; age: 61.29 ± 14.49 years) met study criteria. The average procedure duration was 45.09 ± 38.26 min. Successful recanalization post-ADAPT (thrombolysis in cerebral infarction 2b-3) was achieved in 72.6% (53/73) of patients. Good functional outcome (Modified Rankin Scale 0–2) at 3 months was achieved in 50.7% (37/73), with poor functional outcome in 24.7% (18/73). The 90-day mortality rate was 24.7% (18/73). The hemorrhagic transformation rate was 31.6%, in which 19.2% were symptomatic. Vessel perforation occurred in 5.5% (4/73) of patients but in all cases was associated with the guidewire and not the reperfusion catheter. Vessel dissection occurred in 1.4% (1/73) and vasospasm in 5.5% (4/73) of patients. Conclusion: Mechanical thrombectomy using ADAPT with large-bore catheters for acute ischemic stroke due to LVO is a method that yielded good results in recanalization and clinical recovery in a Vietnamese patient population.

Developing critical thinking for students has recently gained significant attention in global educational discourse and practices, in response to social demands for autonomous citizens in a knowledge-based economy. In Vietnam, the objective of developing critical thinking for students has now become one of the central focuses in the new general educational program required by the government. However, a critical review of literatures on critical thinking, the new general educational program, and practices of teaching and learning in Vietnamese schools, reveals a number of potential hindrances for the changes, including a lack of clear and detailed guidance in the new program regarding critical thinking, teachers' beliefs and teaching habits, a passive and examination-oriented learning culture, and traditions of hierarchy and face saving. To make teaching for critical thinking reality, there needs to be cooperation and participation from all parties from policy makers to teacher-training universities, local educational departments, schools, families, teachers and students in establishing a clear schedule for the implementation of a social constructivist approach in teaching and learning.

Recycling fly ashes is a good alternative to disposal with the significant economic and environmental benefits. Characterization of fly ashes can be helpful to evaluate their use potentials. This study aimed to investigate the physical, chemical and mineralogical properties of fly ashes from five thermal power stations in Northern Vietnam in relation to use as sandy soil amendments. The results showed that the fly ashes were dominated by silt-sized and spherical particles and had low bulk densities. There was almost not significant difference in the surface charges among the fly ashes; however, their surface areas varied widely. The fly ashes were alkaline. The electrical conductivity and cation exchange capacity in the fly ashes were higher than those in the sandy soil. The concentrations of extractable K, P, Ca 2+ and Mg 2+ in the fly ashes were higher compared with the sandy soil. The major matrix elements in the fly ashes were Si, Al, and Fe together with significant percentages of K, Mg, Ca and Ti. Quartz was the most predominant mineral present in the fly ashes. Several radioactive elements were found in the fly ashes with very low concentrations. The potential to release trace elements from the fly ashes was below the regulatory guidelines. The amendment of fly ashes to the sandy soil led to the substantial decrease in the hydraulic conductivity but the increase in the plant-available water contents of the sandy soil. It is recommended to use the fly ashes as soil amendments for sandy soil amelioration.