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In Vietnamese culture, bamboo holds deep symbolic significance. However, in recent years, as a result of evolving usage patterns and the introduction of alternative materials in the face of a rapidly developing modern market economy, industrialisation, and urbanisation, bamboo's economic and social value has dwindled. Nevertheless, with the pressing challenges of climate change, environmental pollution, and the depletion of natural resources, bamboo is experiencing a resurgence in importance within the lives of Vietnamese people. Ba Be district, situated in Bac Kan province, stands as one of the country's most impoverished regions. Natural bamboo thrives in 14 out of 15 communes, with Dong Phuc commune being the exception. Planted bamboo is found in 14 out of 15 communes, excluding Cho Ra town, covering approximately 7.9 % of the entire district's natural area (NA). The district's vast terrain, featuring slopes exceeding 15°, presents formidable obstacles to socio-economic development. This study aims to shed light on the distribution of bamboo forests in Ba Be district and presents an assessment of bamboo's suitability within its natural surroundings. The study employs the analytical hierarchy process (AHP) method and spatial statistics, using remote sensing data supplied by the Department of Natural Resources and Environment, Ba Be district. The results demonstrate that 60 % of Ba Be district's NA is conducive to bamboo cultivation and growth. The findings of this research provide local authorities with a scientifically grounded basis for strategic planning, enabling bamboo to emerge as a pivotal resource within production forests. This approach outlines the ideal spatial distribution for bamboo cultivation and development, ultimately fostering the sustainable utilisation of local natural resources to support both immediate and long-term local socio-economic development.

SiC based pressure sensors show tremendous promise for harsh environment applications thanks to their excellent mechanical, electrical, thermal, and chemical properties. This paper presents the design, fabrication, and characterisation of a highly sensitive and robust 3C-SiC/Si pressure sensor. The sensor utilises a stress amplification structure consisting of four Si pillars built up from the 3C-SiC/Si membrane, supporting a series of released n-type 3C-SiC sensing elements. When pressure is applied to the diaphragm, the pillars act to locally concentrate and amplify strain in the 3C-SiC sensing elements, resulting in over 7 times higher stresses/strains in these sensing elements compared to a traditional structure. Additionally, the front side of the sensor is fully covered by a 3C-SiC thin film, which provides a strong chemical protective capability, allowing the sensor to operate in harsh chemically corrosive environments. The robust device utilises the full Wheatstone bridge to negate the effects of temperature. Experimental results show that the fabricated sensor is highly stable, repeatable, has a high sensitivity of 0.276 mV/V/kPa and a maximum non-linearity of 2.2 % in the 0–100 kPa region. The results indicate that this smart-structure pressure sensor is promising for applications that require highly precise pressure sensing in aggressively corrosive environments.

Catechol 1,2-dioxygenase (CAT1) is a key enzyme for the ortho-cleavage pathway involved in the degradation of dibenzofuran, a dioxin derivative, which is a highly toxic environmental pollutant. The present study aims to investigate appropriate culture conditions for enhancing the expression of the cat1 gene encoding CAT1 enzyme from Burkholderia cepacia DF4 in Escherichia coli M15. The optimized culture conditions for gene expression are cell density at the time of induction, shaking speed, induction temperature, induction time, and inducer concentration. The highest level for CAT1 was obtained at the IPTG concentration of 1.2 mM, 10 hours after induction at 35 °C, shaking speed 200 rpm with cell density at OD600 0.7.

Calcium phosphate (CaP) coating on melt electrowritten (MEW) substrates is a potential candidate for bone regeneration influencing the interaction of osteoblasts with implanted scaffolds. Pretreatment to improve hydrophilicity of the hydrophobic polymer fibres affects subsequent coating with bioactive compounds like CaP. Therefore, this study evaluated the subsequent stability and structural properties of CaP coated MEW Poly-ε-caprolactone (PCL) scaffolds following pre-treatment with either argon-oxygen plasma or sodium hydroxide (NaOH). Scanning electron microscopy and μ-CT showed uniform CaP coating after one hour immersion in simulated body fluid following plasma pretreatment. Moreover, fourier transform infrared spectroscopy, energy dispersive spectrometry and X-ray diffraction analysis confirmed the presence of hydroxyapatite, tetracalcium phosphate and halite structures on the coated scaffolds. Contact angle measurement showed that the plasma pretreatment and CaP coating improved the hydrophilicity of the scaffold. However, the mechanical properties of the scaffolds were degraded after both plasma and NaOH treatments. The tensile stability was significantly improved following mineralization in plasma-treated scaffolds due to the smaller crystal size formed on the surface resulting in a dense CaP layer. The results obtained by thermogravimetric analysis also confirmed higher deposition of CaP particles on coated scaffolds following plasma modification. The results of this study show that plasma pre-treated mineralized MEW PCL scaffolds are sufficiently stable to be useful for further development in bone regeneration applications. Keywords: Calcium phosphate coating, Polycaprolactone, Melt electrowriting, Apatite mineralization, Plasma treatment, Bone regeneration

E-skin with physical sensing capability has attracted considerable interest towards practical applications in soft robotics, human–machine interfaces, and wearable health monitoring. However, the development of a multimodal sensing platform with multiple layers for e-skin sensing of temperature and pressure has faced challenges due to the typical use of bare or single sensing layers as well as the complication of integration of multifunctional sensing modules onto curved surfaces. Herein, we demonstrate a new platform technology with multiple sandwiched layers of highly oriented carbon nanotube (CNT) films and polyacrylonitrile (PAN) for integration of pressure and temperature sensory functionalities into a single platform that is thin, ultra-lightweight, flexible, and wearable. The key technology of in-situ deposition of sensor platform on objects or in robot interface makes this a unique method for the development of e-skins for robotic applications, offering a new approach to wearable electronics and portable health care.

The main objective of this paper is to introduce fuzzy sequential patterns with fuzzy time-intervals in quantitative sequence databases. In the fuzzy sequential pattern with fuzzy time-intervals, both quantitative attributes and time distances are represented by linguistic terms. A new algorithm based on the Apriori algorithm is proposed to find the patterns. The mined patterns can be applied to market basket analysis, stock market analysis, and so on.

Candida albicans is an opportunistic pathogen involved in many infections, especially linked to implanted medical devices. Its ability to form biofilms complicates the treatment of these infections as few molecules are active against sessile C. albicans. The aim of this study was to evaluate the potential of leaves, three-month-old and one-year-old stems of Rubus idaeus L. against C. albicans biofilm growth. Extractions with a polarity gradient were carried out on hydroacetonic extracts and followed by fractionation steps. The obtained extracts and fractions were tested for their anti-biofilm growth activity against C. albicans using XTT method. Compounds of active subfractions were identified by LC-MS. The hexane extracts from leaves and stems were the most active against the fungus with IC50 at 500 and 250 µg/mL. Their bioguided fractionation led to 4 subfractions with IC50 between 62.5 and 125 µg/mL. Most of the components identified in active subfractions were fatty acids and terpenoïds.

Flood hazards affect the local economy and the livelihood of residents along the South-Central Coast of Vietnam. Understanding the factors influencing floods’ occurrence potentially contributes to establish mitigation responses to the hazards. This paper deals with an empirical study on applying a combination of the fuzzy analytic hierarchy process (AHP), the fuzzy technique for order of preference by similarity to ideal solution (TOPSIS), and a geographic information system (GIS) to assess flood hazards along the South-Central Coast of Vietnam. Data are collected from focus group discussions (FGDs) with five communal authorities; a questionnaire completed by eight hamlet heads in the Phuoc Thang commune (Binh Dinh province); and documents, reports, and thematic maps provided from official sources. A total of 12 maps of flood factors are prepared. The results show that terrain elevation, creek-bottom terrains, high tide-induced flooding area, and distance to water body are the main factors affecting flood hazards. The An Loi hamlet faces the highest risk for floods, followed by Lac Dien, Luong Binh, and Pho Dong. The map of flood hazards indicates the western part is assessed as low hazard, whereas the eastern part is a very high hazard area. The study findings show that the hybrid approach using GIS-based fuzzy AHP–TOPSIS allows connecting decision makers with the influencing factors of flooding. To mitigate floods, both the Vietnam national government and the Binh Dinh provincial government should integrate natural hazard mitigation into socio-economic development policies.

A flexible pressure sensor with a rudimentary, ultra-low cost, and solvent-free fabrication process is presented in this paper. The sensor has a graphite-on-paper stacked paper structure, which deforms and restores its shape when pressure is applied and released, showing an exceptionally fast response and relaxation time of ≈0.4 ms with a sensitivity of −5%/Pa. Repeatability of the sensor over 1000 cycles indicates an excellent long-term stability. The sensor demonstrated fast and reliable human touch interface, and successfully integrated into a robot gripper to detect grasping forces, showing high promise for use in robotics, human interface, and touch devices.

A piezoelectrically actuated valveless micropump has been designed and developed. The principle components of this system are piezoelectrically actuated (PZT) metal diaphragms and a complete fluid flow system. The design of this pump mainly focuses on a cross junction, which is generated by a nozzle jet attached to a pump chamber and the intersection of two inlet channels and an outlet channel respectively. During each PZT diaphragm vibration cycle, the junction connecting the inlet and outlet channels with the nozzle jet permits consistencies in fluidic momentum and resistances in order to facilitate complete fluidic path throughout the system, in the absence of any physical valves. The entire micropump structure is fabricated as a plate-by-plate element of polymethyl methacrylate (PMMA) sheets and sandwiched to get required fluidic network as well as the overall device. In order to identify the flow characteristics, and to validate the test results with numerical simulation data, FEM analysis using ANSYS was carried out and an eigenfrequency analysis was performed to the PZT diaphragm using COMSOL Multiphysics. In addition, the control system of the pump was designed and developed to change the applied frequency to the piezoelectric diaphragms. The experimental data revealed that the maximum flow rate is 31.15 mL/min at a frequency of 100 Hz. Our proposed design is not only for a specific application but also useful in a wide range of biomedical applications.

In this paper, we report on the design, simulation, and experimental analysis of a miniaturized device that can generate multiple circulated jet flows. The device is actuated by a lead zirconate titanate (PZT) diaphragm. The flows in the device were studied using three-dimensional transient numerical simulation with the programmable open source OpenFOAM and was comparable to the experimental result. Each flow is verified by two hotwires mounted at two positions inside each consisting chamber. The experiment confirmed that the flow was successfully created, and it demonstrated good agreement with the simulation. In addition, a prospective application of the device as an angular rate sensor is also demonstrated. The device is robust, is minimal in size, and can contribute to the development of multi-axis fluidic inertial sensors, fluidic amplifiers, gas mixing, coupling, and analysis.

This paper reports on the design and simulation of a valveless micro pump which promises widely applicable in microfluidic applications. The structure of the pump comprises a PZT diaphragm and a fluidic network channel which can be easily fabricated by either conventional machining or silicon micromachining techniques. The working principle of the pump relies on the structure of the cross junction which connects the pump chamber, the outlet and two opposite inlet channels. This design allows a difference of fluidic resistance and momentum between the pump phases which results in a net flow from the inlet to outlet. The pump performance is studied by numerical simulation by applying the deformation of the PZT diaphragm. Experiments of the prototype had been conducted and working principle was confirmed.

Abstract Background Despite the increasing prevalence of type 2 diabetes in urban areas, relatively little has been known about its actual prevalence and its associations in rural areas, Vietnam. The purpose of this study was to evaluate the prevalence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), diabetes and their risk factors in a rural province, Vietnam. Methods A cross–sectional study with a representative sample was designed to estimate the hyperglycemia prevalence, using 75–g oral glucose tolerance test. Potential risk factors for hyperglycemia were analyzed using multinomial logistic regression, taken into account influences of socio–economic status, anthropometric measures, and lifestyle–related factors. Results The age and sex–adjusted prevalence rates (95% CI) of isolated IFG, isolated IGT, combined IFG–IGT, and diabetes were 8.7 (7.0–10.5), 4.3 (3.2−5.4), 1.6 (0.9−2.3), and 3.7% (2.7–4.7%), respectively. There were still 73% of diabetic subjects without knowing the condition. Blood pressure, family history of diabetes, obesity–related measures (waist circumference, waist–hip ratio, body fat percentage, and abdominal obesity) were the independent risk factors for hyperglycemia (IFG, IGT, and diabetes). Conclusions The prevalence of hyperglycemia in rural areas has not been as sharply increased as that reported in urban cities, Vietnam. Blood pressure and obesity–related measures were the most significant predictors for hyperglycemia level and they can be taken into account in building prognosis models to early detection of diabetes in rural Vietnamese populations.