14 research outputs found

    Preparation of Ti/TiO2-PANi electrodes by combining method of thermal treatment with polymerization processing and their electrochemical property

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    Ti/TiO2-PANi-electrodes were synthesized by combining method of thermal treatment of titanium substrate with chemical polymerization processing of aniline on which. Their morphological structure was observed by scanning electron microscopy. The presence of PANi and TiO2 were indicated by infrared spectra and X-ray diffraction, respectively. Their electrochemical properties were characterized by cyclic voltammetry and impedance spectroscopy. The results showed that their photoelectrochemical property with light on in 0.5 M H2SO4 indicating a n-conductor that depended on PANi thickness covered TiO2-layer among them the best one obtained by oxidative temperature of 500 oC for 30 minutes during thermal treatment of titanium substrate connected with an immersing into acidic aniline solution for only 8 min during polymerization

    A Novel Wideband Circularly Polarized Antenna for RF Energy Harvesting in Wireless Sensor Nodes

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    A novel wideband circularly polarized antenna array using sequential rotation feeding network is presented in this paper. The proposed antenna array has a relative bandwidth of 38.7% at frequencies from 5.05 GHz to 7.45 GHz with a highest gain of 12 dBi at 6 GHz. A corresponding left-handed metamaterial is designed in order to increase antenna gain without significantly affecting its polarization characteristics. The wideband circularly polarized antenna with 2.4 GHz of bandwidth is a promising solution for wireless communication system such as tracking or wireless energy harvesting from Wi-Fi signal based on IEEE 802.11ac standard or future 5G cellular. A potential application of this antenna as a receiving antenna for RF-DC device to obtain DC power for a wireless sensor node from Wi-Fi signal is shown

    Echinacea purpurea: An overview of mechanism, efficacy, and safety in pediatric upper respiratory infections and otitis media

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    Pediatric upper respiratory infections (URIs) and otitis media (OM) significantly impact the health of children globally. Echinacea purpurea, known for its immunomodulatory, anti-inflammatory, and antimicrobial properties, has been historically used to treat various ailments, suggesting its potential as an adjunctive treatment in pediatric respiratory conditions. This narrative review synthesizes literature from January 2000 to December 2023 on the efficacy and safety of E. purpurea in treating pediatric URIs, including OM. It focuses on clinical trials and empirical studies that explore the mechanisms of action, such as the modulation of cytokine production, inhibition of NF-κB signaling, and antimicrobial effects. The analysis reveals mixed outcomes regarding the efficacy of E. purpurea in pediatric populations, attributed partly to variability in study designs and lack of standardized treatment protocols. While some studies report reduced severity and duration of respiratory symptoms, others indicate minimal or no significant difference compared to placebo. The review also highlights the need for specifically designed products that cater to the unique physiological and metabolic needs of children. Rigorous, well-designed clinical trials are crucial for establishing clear guidelines on the use of E. purpurea in pediatric respiratory care, ensuring its safe and effective application in improving health outcomes for children

    A value perspective of service interaction quality: The case of immigrants returning to native countries as medical tourists

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    Marketing literature shows that the interaction between service encounters and customers is essential for the value creation process. However, little is known about how interaction contributes to customer value in the special context of immigrants living in more-developed countries, who return to their native countries for medical service. Based on the data collected from overseas Vietnamese, this study investigates the effects of interaction quality on different forms of service value, leading to positive word-of-mouth. The findings indicate that interaction quality strongly affects customer perception of quality value and social value and moderately affects price value. In turn, these three forms of value significantly affect positive word-of-mouth. By linking perceived quality, social and price value with word-of-mouth, the present study suggests an effective way to promote this special form of medical service to immigrants living outside the country

    BẢN CHẤT LIÊN KẾT HÓA HỌC CỦA CLUSTER Si2M VỚI M LÀ MỘT SỐ KIM LOẠI HÓA TRỊ I (Li, Na, K, Cu và Cr)

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    The density functional theory at the B3P86/6-311+G(d) level was used to study the geometric structures, stability, and chemical bonding of doped silicon clusters Si2M (M = Li, Na, K, Cu, and Cr). The results reveal that the most stable isomers of Si2M have isosceles triangle structure with the C2v symmetry, existing in two quasi-degenerate electronic states of A1 and B1 at the same spin multiplicity (doublet or quintet). The Si–M bonds are mainly formed via the electron transfer from the AO-s of M atoms to the Si2 moiety in the case of M being Li, Na, and K, while via the overlap between AO-s and AO-3d of Cu, Cr atoms and the MO-s of the Si2 moiety. The Si2Cr cluster is the most stable in the considered clusters.Công trình này công bố kết quả nghiên cứu cấu trúc, độ bền và bản chất liên kết hóa học của các cluster silic pha tạp Si2M với M là một số kim loại hóa trị I bằng phương pháp phiếm hàm mật độ tại mức lý thuyết B3P86/6-311+G(d). Theo kết quả thu được, đồng phân bền của các cluster pha tạp Si2M có cấu trúc tam giác cân, đối xứng C2v và tồn tại hai trạng thái giả suy biến có cùng độ bội spin (A1 và B1). Kết quả thu được cho thấy liên kết Si-M được hình thành chủ yếu từ sự chuyển electron từ AO-s của các nguyên tử Li, Na, K, Cu, Cr sang khung Si2 và sự xen phủ của các AO-d của nguyên tử Cu, Cr với AO của khung Si2. Kết quả nghiên cứu các cluster Si2M (M là Li, Na, K, Cu, Cr) cho ra kết luận rằng cluster Si2Cr là bền nhất

    Improving Irrigation Water Use Efficiency of Robusta Coffee (Coffea canephora) Production in Lam Dong Province, Vietnam

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    Recent prolonged dry periods and lack of irrigation water have severely affected the productivity of coffee farms in the Central Highlands of Vietnam. This paper analyzes the efficiency of irrigation water use for Robusta coffee (Coffea canephora) in the Lam Dong province. A Cobb–Douglas production function was used to determine coffee productivity’s response to the application of irrigation water and other production factors using data collected from 194 farmers, while the technical efficiency (TE) and irrigation water use efficiency (IWUE) were analyzed using a data envelopment analysis (DEA) model. The correlation of different factors to IWUE was determined using the Tobit model. The production function analysis using Cobb–Douglas shows that the volume of irrigation water, amount of working capital, labor, and farm size significantly influence coffee productivity. Indigenous farmers are more efficient in utilizing irrigation water than migrant farmers. The Tobit result indicates that farmers’ experience, education level, the distance of farm to water sources, security of access to water sources, extension contact, and credit access significantly affect IWUE. The study findings further suggest that mitigating water shortages in coffee farms require subregional and national policy support such as better access to credit and extension services, training, land management, and household-level efforts to improve farming practices through the application of appropriate technologies and traditional knowledge

    Preliminary Observation of Native Glyptostrobus pensilis (Taxodiaceae) Stands in Vietnam

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    Results of preliminary studies of last remnants of Glyptostrobus pensilis native populations in Vietnam are presented in the paper in form of standard taxonomical treatment with comments on ecology, population structure and natural conditions of its habitats. Perspectives of conservation of this unique Tertiary relict are specially assessed and discussed

    A complex case of necrotizing pneumonia and parapneumonic effusion in a healthy 20-month-old child: Successful management with video-assisted thoracoscopic surgery and chest tube placement

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    Necrotizing pneumonia (NP) is characterized by destruction of pulmonary tissue, resulting in multiple thin-walled cavities. There are limited reports on NP and parapneumonic effusion cases in children associated with Pseudomonas aeruginosa. Currently, there is no consensus regarding the optimal timing for video-assisted thoracoscopic surgery (VATS) following failure of chest tube placement and antibiotic treatment. A healthy 20-month-old child was hospitalized with symptoms of community-acquired pneumonia, progressing to severe NP and parapneumonic effusion. Despite receiving broad-spectrum antibiotics and chest tube placement on the third day of treatment, the condition continued to deteriorate, prompting VATS intervention on the sixth day. The presence of a “split pleural sign“ and extensive lung necrosis on chest computed tomography contributed to initial treatment failure. Multidrug resistance P. aeruginosa was identified through nasal trachea aspiration specimens on the eighth day of treatment, leading to an adjustment in antibiotic therapy to high-dose meropenem and amikacin. Subsequently, the patient became afebrile, showed clinical improvement, and was discharged after 35 days of treatment. Through this case, we aim to emphasize an unusual pathogenic bacteria in the context of NP and the need for standardized surgical interventions in pediatric patients with NP

    Sol-gel prepared of LaMnO3 perovskite: characterisation and catalytic activity in 2-phenylbenzo[d]imidazo[2,1-b]thiazole synthesis

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    In this work, LaMnO3 was prepared by the sol-gel method followed by thermal treatment. The catalytic activity of LaMnO3 in the synthesis of 2-henylbenzo[d]imidazo[2,1-b]thiazole (2-PIT) from 2-aminobenzothiazole and acetophenone was strongly influenced by the calcination temperature. The highest efficiency of samples synthesized at 800◦C was approved due to Lewis acid and oxygen vacancy sites properties which were confirmed through NH3-TPD and H2-TPR. Furthermore, the stability and reusability of the sample demonstrated the potential of LaMnO3 heterogeneous catalysts in organic synthesis applications
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