An angle-compensating colorimetric strain sensor with wide working range and its fabrication method.

The visual response is one of the most intuitive principles of sensors. Therefore, emission and change of the colors are widely studied for development of chemical, thermal and mechanical sensors. And it is still a challenging issue to fabricate them with a simple working mechanism, high sensitivity, good reliability, and a cost-effective fabrication process. In this study, we propose a mechanical strain sensor, which has 2D photonic crystal structures in nanoscale on stretchable polydimethylsiloxane (PDMS) substrate. Due to the periodic nanostructures, the surface of the sensor produces structural colors. And when it is stretched, the periodicity of the nanostructures changes, which results in the shift of the colors. Multiple nanostructures with different periodicities are integrated on the sensor in order to extend the working range up to 150% with high sensitivity. In addition, reusable and robust molds, which are fabricated by self-assembly of nanoparticles, are used for multiple replications of sensor substrates. Thus, the fabrication process of this study is believed to be potential for possible industrial manufacturing. This study is expected to contribute to strain sensors in the future for the applications of health care, infrastructure monitoring, soft robotics, and wearable devices.

Secondary metabolites from Valeriana jatamansi with their anti-inflammatory activity.

Valeriana jatamansi is hired as multiple remedies for treatment of insomnia, blood and circulatory disorders, asthma, dry cough, jaundice, seminal weakness, cardiac debility, and skin diseases in Vietnam. Our research discovered the phytochemical investigation of constituents from this herbal medicine resulted in the isolation of two new compounds (jatamansides A (4) and B (7)) together with 16 known ones from the whole plant. Their structures were established by using spectroscopic techniques (multinuclear and multidimensional nuclear magnetic resonance, infrared, ultraviolet-visible), mass spectrometry, hydrolysis analysis, or comparing their NMR data to those reported in the literature. In addition, all the isolates were evaluated for their inhibitory effect against TNF-α production in LPS-stimulated on RAW264.7 cells with significant inhibition.

Fabrication of robust and reusable mold with nanostructures and its application to anti-counterfeiting surfaces based on structural colors.

In this study, we report a method to fabricate molds and flexible stamps with 2D photonic crystal structures. This includes self-assembly of polystyrene particles into monolayer, oxygen reactive ion etching, thin film (chromium (Cr)) deposition, and polydimethylsiloxane replication. By tuning the thickness of Cr layer, reusable master molds with nano bumps or nano concaves could be prepared selectively. We showed that the replicated flexible stamps out of these molds exhibited structural colors. Characteristics of the colors depended on viewing angle, brightness of background and light source. And the colors even faded out when the background is white or when the stamp was bent. By using this feature, possible strategies for anti-counterfeiting applications have been suggested in this study. Since the molds are reusable and the fabrication method is simple and cost-effective, this study is expected to contribute to nano devices for industries in future.

Chemical constituents of Vietnamese mangrove Hibiscus tiliaceus with antioxidant and alpha-glucosidase inhibitory activity.

Using various chromatographic techniques, a total of 15 compounds, including one novel megastigmane named tiliaceic acid A (1) and 14 known compounds, were isolated from the traditional medicinal Vietnamese mangrove Hibiscus tiliaceus. Their structures were confirmed based on spectroscopic experiments including, UV, 1 D- and 2 D-NMR, HR-ESI-MS, and ECD analysis. The antioxidant and α-glucosidase inhibitory activities of the isolated compounds from H. tiliaceus were evaluated for the first time. Compound 2 showed strong α-glucosidase inhibitory activity with an IC50 of 77.78 ± 1.00 µM compared with the positive control acarbose at 105.71 ± 2.29 µM.

Electrochemical oxidation as a post treatment for biologically tannery wastewater in batch reactor.

Tannery wastewater is known to contain high concentrations of organic compounds, heavy metals, nitrogen, sulphur, chromium, and many other chemicals. Both aerobic and anaerobic biological approaches have proven ineffective in the treatment of tannery wastewater due to the high salinity and toxic chemicals contained within the medium. Electrochemical oxidation presents a promising method for solving this problem. High pollutant removal efficiency, low energy consumption, and high electrode stability are three important factors supporting the feasibility of an efficient electrochemical treatment process. In the present study, electrochemical oxidation was performed as a post treatment for tannery wastewater (after biological pre-treatment) in a batch reactor using Ti/RuO2, Ti/IrO2, and Ti/BDD anodes. The effects of pH, current density, stirring rate and treatment time were studied to assess the treatment efficiency as well as the energy consumption of the process. The results showed that colour, chemical oxygen demand (COD), total organic carbon (TOC), and total nitrogen (TN) removal efficiencies on the electrodes were: Ti/RuO2 (88.8%, 88.40%, 64.0%, 96.4%), Ti/IrO2 (85.40%, 85.9%, 52.3%, 51.4%), Ti/BDD (90.60%, 94.7%, 90.5%, 82.7%) respectively, at a current density of 80 mA/cm2. All three electrodes demonstrated optimal performance at a pH of 8, a stirring rate of 400 rpm, a current density of 80 mA/cm2, and an electrolysis time of 5 h. The concentration of tri-chloromethane by-product was detected with limiting value. Electrochemical oxidation thus offers a feasible method for removing organic compounds and nutrients from tannery wastewater.

Effect of sonication characteristics on stability, thermophysical properties, and heat transfer of nanofluids: A comprehensive review.

The most crucial step towards conducting experimental studies on thermophysical properties and heat transfer of nanofluids is, undoubtedly, the preparation step. It is known that good dispersion of nanoparticles into the base fluids leads to having long-time stable nanofluids, which result in having higher thermal conductivity enhancement and lower viscosity increase. Ultrasonic treatment is one of the most effective techniques to break down the large clusters of nanoparticles into the smaller clusters or even individual nanoparticles. The present review aims to summarize the recently published literature on the effects of various ultrasonication parameters on stability and thermal properties of various nanofluids. The most common methods to characterize the dispersion quality and stability of the nanofluids have been presented and discussed. It is found that increasing the ultrasonication time and power results in having more dispersed and stable nanofluids. Moreover, increasing the ultrasonication time and power leads to having higher thermal conductivity and heat transfer enhancement, lower viscosity increase, and lower pressure drop. However, there are some exceptional cases in which increasing the ultrasonication time and power deteriorated the stability and thermophysical properties of some nanofluids. It is also found that employing the ultrasonic horn/probe devices are much more effective than ultrasonic bath devices; lower ultrasonication time and power leads to better results.

Quality of Life and Suitability with Vietnamese Harmonious Face Index in Class III Malocclusion Patients.

BACKGROUND: Maxillary Lefort I osteotomy, mandibular bilateral sagittal split ramus was frequently used in correcting skeletal class III malocclusion. There was a lack of research on class III malocclusion patients' quality of life (QoL) after bimaxillary osteotomy. AIM: Class I Intermaxillary relationship was achieved, aesthetic was significantly improved. Significant improvement in Class III skeletal patients' quality of life was acquired. The achievement of harmonious face would be beneficial to the facial aesthetics of patients, thus improving the quality of life. METHODS: Harmonious face index is an effective criterion in assessing the surgery's outcome. In this study was conducted on 30 patients at Hanoi National Hospital of Odontostomatology, Viet Duc Hospital, and Hong Ngoc Hospital from April 2017 to April 2018, and it was a quasi-experimental study with self-comparison, 12 months follow up. RESULTS: Orthognathic surgery effectively corrected malocclusion crossbite, dental compensation, and helped to improve facial aesthetics. 100% of patients had the quality of life improved, good quality of life consisted of 86.7%. In comparison with a harmonious facial index of Kinh ethnic in Vietnam, 70% of patients achieved skeletal harmony, 63.3% of patients achieved dental harmony, 80% achieved soft tissue harmony. CONCLUSIONS: Vietnamese harmonious facial index should be used in planning and pre-surgical simulation.

Treatment of Anti-NMDA Receptor Encephalitis with Ovarian Teratoma Removal: A Literature Review and Two Case Reports.

BACKGROUND: N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis appears common in the world, but the number of clinical cases in Vietnam which were recorded is rare. CASE REPORT: We describe two new cases of disease in recent years with the aim of contributing to diagnosis and treatment experiences. These cases were noted over the past 3 years with the patients who have been treated at lower levels but have no results. They came to us when symptoms became worse and therefore required prolonged treatment with special intensive care facilities. The atypical and easily confused symptoms are the reasons that make the disease be detected late; leading to a much higher cost of treatment and the complication may appear in the patient. In the past, patients with these manifestations were diagnosed with unexplained encephalitis and severe sequelae or death. Autoimmune encephalitis has many types; NMDA encephalitis associated with ovarian teratoma is the most common autoimmune encephalitis in young women. CONCLUSION: In conclusion, based on the case report, we hope to contribute some experiences on the diagnosis and the strategy in early treatment. With most female patients at very young age, early treatment to avoid complications will help patients have a quality life and maintain reproductive function.

A randomized controlled pilot study of artesunate versus triclabendazole for human fascioliasis in central Vietnam.

Human fascioliasis caused by Fasciola hepatica or Fasciola gigantica is an increasing global problem. The mainstay of current treatment is triclabendazole, but resistance in animals has been described, and it is not available in many countries. The antimalarial artesunate has an excellent safety profile, and there is increasing evidence of its efficacy against other parasites both in vitro and in vivo. We performed a study to investigate the usefulness of artesunate in symptomatic human fascioliasis; 100 patients were enrolled. Patients treated with artesunate were significantly more likely to be free of abdominal pain at hospital discharge (50/50 versus 44/50, P = 0.027, relative risk 1.14, 95% confidence interval 1.03-1.26), but the complete response rate at 3 months was lower than for patients treated with triclabendazole (38/50 versus 46/50, P = 0.05, RR 0.83, 95% CI 0.69-0.98, artesunate versus triclabendazole). There may be a role for artesunate in fascioliasis.

Optimization and limitation of calcium ionophore to generate DCs from acute myeloid leukemic cells.

PURPOSE: Calcium ionophore (CI) is used to generate dendritic cells (DCs) from progenitor cells, monocytes, or leukemic cells. The aim of this study was to determine the optimal dose of CI and the appropriate length of cell culture required for acute myeloid leukemia (AML) cells and to evaluate the limitations associated with CI. MATERIALS AND METHODS: To generate leukemic DCs, leukemic cells (4x10(6) cells) from six AML patients were cultured with various concentrations of CI and/or IL-4 for 1, 2 or 3 days. RESULTS: Potent leukemic DCs were successfully generated from all AML patients, with an average number of 1.2x10(6) cells produced in the presence of CI (270 ng/ml) for 2 days. Several surface molecules were clearly upregulated in AML cells supplemented with CI and IL-4, but not CD11c. Leukemic DCs cultured with CI had a higher allogeneic T cell stimulatory capacity than untreated AML cells, but the addition of IL-4 did not augment the MLR activity of these cells. AML cells cultured with CI in the presence or absence of IL-4 showed increased levels of apoptosis in comparison to primary cultures of AML cells. CONCLUSION: Although CI appears to be advantageous in terms of time and cost effectiveness, the results of the present study suggest that the marked induction of apoptosis by CI limits its application to the generation of DCs from AML cells.