Objective assessment of movement disabilities using wearable sensors

The research presents a series of comprehensive analyses based on inertial measurements obtained from wearable sensors to quantitatively describe and assess human kinematic performance in certain tasks that are most related to daily life activities. This is not only a direct application of human movement analysis but also very pivotal in assessing the progression of patients undergoing rehabilitation services. Moreover, the detailed analysis will provide clinicians with greater insights to capture movement disorders and unique ataxic features regarding axial abnormalities which are not directly observed by the clinicians

SYNTHESIS OF STARCH MODIFIED MONTMORILLONITE AS AN EFFECTIVE ADSORBENT FOR Pb (II) REMOVAL FROM WATER

The adsorbent is prepared by the montmorillonite co-modification with starch for the removal of Pb (II) ions from aqueous solution. The Fourier-transformed infrared (FTIR), X-ray diffraction (XRD) spectroscopies were used to determine the structure and characteristics of the adsorbent. The main factors affecting the removal of Pb (II) ions were investigated, including the effect of pH, contact time, adsorbent dosage and the initial concentration of Pb (II). Batch process can be used for adsorption and equilibrium studies. The experimental data were fitted using Freundlich and Langmuir adsorption models. The Langmuir isotherm best fitted the experimental data with R2 0.99 and maximum Pb (II) adsorption capacity of 21.5 mg/g indicated monolayer adsorption. Kinetic studies using pseudo-first-order and pseudo-second-order rate models showed that the process complied well with the pseudo second-order rate model

Biocompatible chitosan-functionalized upconverting nanocomposites

Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL–1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL–1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications

A DSC/TGA STUDY OF THE HETEROGENEOUS NUCLEATION OF CRYSTALLIZATION IN POLYPROPYLENE COPOLYMER

The study is aimed at the evaluation of the influence of nucleating agent (t-butyl)benzoic aluminum (NA) in changing clarity, crystallization temperature (Tp) and radiation resistant properties of polypropylene copolymer, PP (co) with 6% of ethylene. It has been shown that crystallization temperature of PP (co)+NA did not change when the content of the NA less than 2%, but the super cooling temperature is a little bit increased when the content of the NA was 2 or higher than 2%. Clarity of the blend comprising of PP (co)+NA decreases with the addition of 2% or more NA (t-butyl)benzoic aluminum. However, the increase of the supercooling temperature makes possible to improve radiation resistance of the material

Study Structure and Properties of Nanocomposite Material Based on Unsaturated Polyester with Clay Modified by Poly(ethylene oxide)

In recent years, polymer clay nanocomposites have been attracting considerable interests in polymers science because of their advantages. There are many scientists who researched about this kind of material and demonstrated that when polymer matrix was added to little weight of clay, properties were enhanced considerably. Because clay is a hydrophilic substance so it is difficult to use as filler in polymer matrix having hydrophobic nature, so clay needs to be modified to become compatible with polymer. In this study, poly(ethylene oxide) was used as a new modifier for clay to replace some traditional ionic surfactants such as primary, secondary, tertiary, and quaternary alkyl ammonium or alkylphosphonium cations having the following disadvantages: disintegrate at high temperature, catalyze polymer degradation, and make nanoproducts colorific, and so forth. In order to evaluate modifying effect of poly(ethylene oxide), modified clay products were characterize d by X-ray spectrum. Then organoclay was used to prepare nanocomposite based on unsaturated polyester. Morphology and properties of nanocomposites were measure d by X-ray diffraction, transmission electron microscopy, tensile strength, and thermal stability. The results showed that clay galleries changed to intercalated state in the nanocomposites. Properties of nanocomposites were improved a lot when the loading of the organoclay was used at 1 phr

Some results of research and forecasting of groundwater salinization in the coastal zone of Soc Trang province

In recent years, the situation of salinity intrusion is very complicated and becomes more serious in the coastal area of Soc Trang province. In this research, SEAWAT modified water density flow model was used to forecast the salinity intrusion for Holocene aquifer (qh) and upper Pleistocene aquifer (qp3) according to the water use planning scenario. The results show that the impact of groundwater extraction process increases the TDS content in the aquifer, the salt water/fresh water areas change over time, the trend of salinity change increases. In Holocene aquifer, salt water area is relatively large and the TDS concentration increases towards the sea, however, fresh water area changes inconsiderably: In 2015 accounting for 17.42% and by 2030 accounting for 17.77% of aquifer area. In upper Pleistocene aquifer, the fresh water area declines significantly: In 2015 accounting for 9.35% and by 2030 only accounting for 7.53% of aquifer area

QUÁ TRÌNH CHUYỂN PHA PHI CÂN BẰNG CỦA VẬT LIỆU HAI CHIỀU PENTA-GRAPHENE

Graphene has received enormous attention in the semiconductor industry during the last two decades. However, since graphene is a gapless semiconductor, it has critical challenges to be engineered into semiconductor devices. Recent reports have shown that penta-graphene stands out as a promising semiconductor candidate with an electronic bandgap between 2.2 and 4.3 eV; thus, it can surmount graphene’s obstacles. However, when being heated, penta-graphene can transform its configurations from pentagonal lattices to hexagonal graphene-like heterostructures, resulting in a significant electronic modification. In this paper, we investigate the effect of heating rates on the non-equilibrium phase transition of a two-dimensional penta-graphene by using molecular dynamic simulations. We have shown that, with a fast-heating process, penta-graphene naturally transforms to graphene without a clear phase separation point. Nevertheless, with a sufficiently slow heating protocol, this transition is a first-order phase transition from a pentagonal to a more stable hexagonal configuration. These results provide the possibility to implement penta-graphene in future optoelectronic devices.Graphene đã được chứng minh là vật liệu mang tính đột phá cho ngành vật liệu bán dẫn. Tuy nhiên, với độ rộng vùng cấm gần như bằng không, graphene có những hạn chế nhất định khi được ứng dụng để chế tạo linh kiện điện tử. Các nghiên cứu gần đây cho thấy penta-graphene với độ rộng vùng cấm 2,2–4,3 eV và độ bền cơ – nhiệt cao có thể dung hòa nhược điểm của graphene. Tuy nhiên, khi bị nung nóng, penta-graphene có thể chuyển từ cấu trúc vòng 5 điển hình sang cấu trúc vòng 6 của graphene, nhưng điều kiện cụ thể để quá trình chuyển pha này hình thành vẫn chưa được nghiên cứu chi tiết. Trong bài báo này, chúng tôi nghiên cứu sự ảnh hưởng của tốc độ nung đến tính chất nhiệt động phi cân bằng của penta-graphene bằng phương pháp mô phỏng động học phân tử. Ở tốc độ nung lớn, penta-graphene sẽ dần chuyển sang graphene mà không có điểm chuyển pha rõ nét. Tuy nhiên, nếu penta-graphene được nung rất chậm, quá trình chuyển pha từ penta-graphene sang graphene là quá trình chuyển pha loại I với sự gián đoạn của thông số nhiệt động tại điểm chuyển pha. Kết quả này sẽ góp phần bổ sung các thông số kỹ thuật quan trọng trong việc ứng dụng vật liệu penta-graphene để chế tạo các linh kiện quang – điện tử trong tương lai

Prospective evaluation of GeneXpert for the diagnosis of HIV- negative pediatric TB cases

Background The GeneXpertMTB/RIF (Xpert) assay is now recommended by WHO for diagnosis of tuberculosis (TB) in children but evaluation data is limited. Methods One hundred and fifty consecutive HIV negative children (<15 years of age) presenting with suspected TB were enrolled at a TB referral hospital in Ho Chi Minh City, Vietnam. 302 samples including sputum (n = 79), gastric fluid (n = 215), CSF (n = 3), pleural fluid (n = 4) and cervical lymphadenopathic pus (n = 1) were tested by smear, automated liquid culture (Bactec MGIT) and Xpert. Patients were classified retrospectively using the standardised case definition into confirmed, probable, possible, TB unlikely or not TB categories. Test accuracy was evaluated against 2 gold standards: [1] clinical (confirmed, probable and possible TB) and [2] ‘confirmed TB’ alone. Results The median age of participants was 18 months [IQR 5–170]. When test results were aggregated by patient, the sensitivity of smear, Xpert and MGIT against clinical diagnosis as the gold standard were 9.2% (n = 12/131) [95%CI 4.2; 14.1], 20.6% (n = 27/131) [95%CI 13.7; 27.5] and 29.0% (n = 38/131) [21.2;36.8], respectively. Specificity 100% (n = 19/19), 94.7% (n = 18/19), 94.7% (n = 18/19), respectively. Xpert was more sensitive than smear (P = <0.001) and less sensitive than MGIT (P = 0.002). Conclusions The systematic use of Xpert will increase early TB case confirmation in children and represents a major advance but sensitivity of all tests remains unacceptably low. Improved rapid diagnostic tests and algorithm approaches for pediatric TB are still an urgent research priority

Throughput Optimization for NOMA Energy Harvesting Cognitive Radio with Multi-UAV-Assisted Relaying under Security Constraints

This paper investigates the throughput of a non-orthogonal multiple access (NOMA)-based cognitive radio (CR) system with multiple unmanned aerial vehicle (UAV)-assisted relays under system performance and security constraints. We propose a communication protocol that includes an energy harvesting (EH) phase and multiple communication phases. In the EH phase, the multiple UAV relays (URs) harvest energy from a power beacon. In the first communication phase, a secondary transmitter (ST) uses the collected energy to send confidential signals to the first UR using NOMA. Simultaneously, a ground base station communicates with a primary receiver (PR) under interference from the ST. In the subsequent communication phases, the next URs apply the decode-and-forward technique to transmit the signals. In the last communication phase, the Internet of Things destinations (IDs) receive their signals in the presence of an eavesdropper (EAV). Accordingly, the outage probability of the primary network, the throughput of the secondary network, and the leakage probability at the EAV are analyzed. On this basis, we propose a hybrid search method combining particle swarm optimization (PSO) and continuous genetic algorithm (CGA) to optimize the UR configurations and the NOMA power allocation to maximize the throughput of the secondary network under performance and security constraints