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•DWCNTs-Gr hybrid thin film was successfully synthesized by LPCVD method.•A novel structure of DWCNTs-Gr hybrid thin film modified SPE was prepared.•An electrochemical sensor using ...ChOx enzyme for detection of As(V) was developed.•A high sensitive sensor was achieved with low LOD for As(V) detection.
In this work, we demonstrate the preparation of hybrid thin films based on double-walled carbon nanotubes and graphene for electrochemical sensing applications. The hybrid films were synthesized on polycrystalline copper foil by thermal chemical vapor deposition under low pressure. This carbonaceous hybrid film has exhibited high transparency with a transmittance of 94.3 %. The occurrence of this hybrid material on the electrode surface of screen-printed electrodes was found to increase electroactive surface area by 1.4 times, whereas electrochemical current was enhanced by 2.4 times. Such a highly transparent and conductive hybrid film was utilized as a transducing platform of enzymatic electrochemical arsenic(V) sensor. The as-prepared sensor shows the linear detection of arsenic(V) in the range from 1 to 10 ppb, with a limit of detection as low as 0.287 ppb. These findings provide a promising approach to develop new multifunctional electrochemical sensing systems for environmental monitoring and biomedical diagnostics.
Background This study aimed to measure the preferences for mental health support among health professionals, their willingness to support the mental health of colleagues and associated factors. ...Method A descriptive cross-sectional study was performed from August to October 2022 within five hospitals located in Hanoi, Vietnam. A total of 244 health professionals participated in the study. Data on socio-economic status, health and COVID-19-related characteristics, Depression Anxiety Stress Scale (DASS-21); and preferences for mental health support services were collected by using a structured self-reported questionnaire. Multivariate logistic regression models were utilized to identify associated factors with the demand for mental support services. Results 13.9%, 17.1% and 8.6% reported having at least mild depression, anxiety and stress, respectively. There 13.9% did not seek any mental health support during the COVID-19 pandemic. The most common support included talking with friends (52.9%), family (50.8%), colleagues (47.6%) and using social networks/Internet (43.5%). There 31.1% had been aware of mental health services, but only 18.0% used this service at least once. Regarding preferences, 47.3% had a demand for mental support services, and the most preferred service was providing coping skills (25.9%), followed by skills to support others against mental problems (22.2%). Major sources of support included psychiatrists (34.4%), colleagues (29.1%) and family (27.9%). The main preferred channels for support included telephone/mobile phone (35.7%) and Internet (20.9%). Only 12.3% were willing to provide mental support for colleagues during the pandemic. Age, education, perceived mental health status, ever seeking any mental service, and DASS-21 depression score were associated with demand for mental support services. Conclusion This study found a lack of awareness of mental health services for health professionals, as well as moderate levels of demand for this service in this population. Raising awareness and developing tailored mental health support services are important to enhancing the mental well-being of health professionals in Vietnam to prepare for the next pandemic.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Nanocomposite structures, where the Fe, Fe
O
, or Ni
O
nanoparticles with thin carbon layers are distributed among a single-wall carbon nanotube (SWCNT) network, are architectured using the co-arc ...discharge method. A synergistic effect between the nanoparticles and SWCNT is achieved with the composite structures, leading to the enhanced sensing response in ammonia detection. Thorough studies about the correlation between the electric properties and sensing performance confirm the independent operation of the receptor and transducer in the sensor structure by nanoparticles and SWCNT, respectively. Nanoparticles with a large specific surface area provide adsorption sites for the NH
gas molecules, whereas hole carriers are supplied by the SWCNT to complete the chemisorption process. A new chemo-resistive sensor concept and its operating mechanism is proposed in our work. Furthermore, the separated receptor and transducer sensor scheme allows us more freedom in the design of sensor materials and structures, thereby enabling the design of high-performance gas sensors.
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•Hydrothermal fabrication of F-surface-modified Sn-doped hematite photoanode.•Obtain the highest photocurrent among the hematite based photoanodes.•F-surface-modification improving ...the surface reaction and charge injection.•The uniform Sn-doping to enhance the charge transport efficiency.
Severe charge recombination and sluggish water oxidation reaction (OER) kinetics significantly limit the practical application of hematite in photoelectrochemical (PEC) water-splitting devices. In this study, fluorine-surface-modified tin-doped hematite (F/Sn:Fe2O3) photoelectrodes have been fabricated by a hydrothermal method incorporated impregnation annealing process. The grown FeOOH nanorods coated with NH4F solution are annealed first at 550 °C in the vacuum to modify the hematite surface and then at 750 °C in argon to promote the diffusion of tin atoms from the fluorine-doped tin oxide (FTO) glass substrate to the hematite structure. The synergistic effect of F-modification and Sn-doping on Fe2O3 electrode considerably enhances its PEC water oxidation performance, resulting in the highest photocurrent density of 3.64 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 G illumination. Both effects increase the carrier concentration in the photoelectrode, which improves its transport efficiency. Moreover, the surface-localized F species promote the OER process on the electrode surface and improve the charge separation at the electrode/electrolyte interface by increasing its hole supply rate under the increased electric field. This work may open a new avenue for fabricating novel photoelectrodes with high PEC water splitting efficiency.
Methylene blue degradation by the UV/TiO2 and UV/TiO2/H2O2 photocatalysis in a suspended photocatalytic reactor coupled with a microfiltration (MF) module is described. The kinetics of methylene blue ...degradation, cake layer formation on the membrane surface, and the energy consumption of the system are evaluated and discussed. In addition, cost estimation of the treatment of methylene blue by different processes is implemented. The investment and operating costs of the photocatalytic membrane reactors are calculated and compared with the UV systems and UV/TiO2‐MF.
An advanced oxidation process based on UV/TiO2/H2O2 was integrated with a cross‐current microfiltration (MF) membrane process for laboratory‐scale methylene blue treatment. Reaction kinetics and wastewater treatment costs were calculated. The cost of treating 1 m3 of methylene blue solution by the UV/TiO2/H2O2‐MF process is about one third lower than that of the UV/TiO2‐MF process.
The degradation of MB on TiO2/BNNS NRs glass substrate was detected by Raman spectroscopy under UV irradiation (254 nm) in the time range of 0–50 min.
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•Boron nitride nanosheets ...decorated titanium dioxide nanorods were synthesized.•Photo-degradation of methylene blue (MB) was evaluated via Raman spectroscopy.•100% degradation of MB achieved in 50 min under UV light (254 nm, 66 W).
Here, we present a facile synthesis of the boron nitride nanosheets decorated titanium dioxide nanorods (TiO2/BNNS NRs) on glass substrates by hydrothermal method. The photocatalytic performance of TiO2/BNNS NRs is investigated by degrading methylene blue (MB) under UV irradiation (254 nm) and recorded by Raman spectroscopy. The obtained results indicated the photocatalytic performance of TiO2/BNNS NRs was significantly improved than that of TiO2 NRs. The rate of degradation (k) of MB was found to be 0.085 min−1 for TiO2/BNNS NRs and 0.052 min−1 for TiO2 NRs. Besides, TiO2/BNNS NRs hybrid structure exhibits high cycling stability with about 90% after 5 consecutive cycles.
In this study, the double hydrothermal method is proposed as a facile approach to the synthesis of ZnTe/ZnO core–shell nanorods. The coating thickness of the p-type ZnTe is varied to adjust the ...junction depth in the n-type ZnO nanorods, and the conductance measurements reveal the change in the conduction path in the heterojunction structures. Structural and chemical investigations conducted using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy confirm the hetero-nanostructure formation of ZnTe/ZnO. The role of ZnTe in H2S-gas sensing by the ZnO nanorods is discussed. The enhanced sensing performance observed with a thin ZnTe coating confirms the importance of the base resistance of the nano-transducer in achieving high response characteristics. The composite structure also demonstrates a superior sensing performance of good repeatability, stability, linearity, and gas selectivity at temperatures greater than 200 °C.
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•Hydrothermal processing for ZnTe coated ZnO-nanorod structures synthesis.•A nano-composite gas sensor whose response is purely controlled by pn junction.•Nano-sensor principle showing the maximum response at the depletion depth scale.•Supporting the depletion model for the conduction type gas sensor device.
(1) Background: This study aims to assess the magnitude of, and factors associated with, depression and anxiety among Vietnamese frontline hospital healthcare workers in the fourth wave of COVID-19; ...(2) Methods: A hospital based cross-sectional study was carried out within two weeks, October 2020, at a central COVID-19 treatment hospital. Depression and anxiety were measured with PHQ-9 and GAD-7, respectively. Bivariate and multivariate logistic regression analysis were applied to recognize variables related to depression and anxiety, respectively; (3) Results: Among 208 frontline hospital healthcare workers, overall prevalence of depressive symptoms, anxiety symptoms, and both symptoms of depression and anxiety was 38.94%, 25.48% and 24.04%, respectively, in healthcare workers. In a reduced model after using multivariate stepwise logistic regression, age (OR = 0.9,
= 0.001), marital status (OR = 7.84,
= 0.027), profession (OR = 0.39,
= 0.028), having experienced traumatic stress following a work event (OR = 46.24,
< 0.001), feeling at very high risk for COVID-19 (OR = 0.02,
< 0.04), and affected by workplace conditions (OR = 5.36,
< 0.001) were associated with the symptoms of depression. With regard to symptoms of anxiety, single status (OR: 12.18,
= 0.002), being medical technician (OR: 68.89,
< 0.001), alcohol use (OR: 6.83,
= 0.014), using pain relief medications (OR: 25.50,
= 0.047), having experienced traumatic stress following a family event (OR: 130.32,
= 0.001), having experienced traumatic stress following a work event (OR: 181.55,
= 0.002), reporting at very high risk for COVID-19 (OR: 29.64,
= 0.011), treating moderate (OR: 6.46,
= 0.038) and severe (OR: 18.96,
= 0.004) COVID-19 patients, and being significantly affected by the community (OR: 6.33,
= 0.003) were increased risk factors for the symptoms of anxiety. Meanwhile, those living with 4-5 people (OR: 0.15,
= 0.011), specializing in infectious disease (OR: 0.13,
= 0.044)/resuscitation and emergency medicine (OR: 0.04,
= 0.046), and having knowledge preparation before participating in COVID-19 (OR: 0.008,
= 0.014) were less associated with the symptoms of anxiety; (4) Conclusions: There was a relatively high prevalence among Vietnamese hospital healthcare workers exhibiting symptoms of depression and anxiety during the ongoing pandemic. Greater attention to training in psychological skills should be suggested for those belonging to a younger age group, being single/widowed/divorced, treating moderate and severe COVID-19 patients, feeling at very high risk for COVID-19, being significantly affected a lot the community or workplace conditions, or experiencing traumatic stress following a family/work event in the past week.
(1) Background: The present study measures the fear of COVID-19 among hospital healthcare workers and identifies several factors associated with increasing fear of COVID-19. (2) Methods: A ...cross-sectional, hospital-based survey was conducted on healthcare workforce recruited from the National Hospital of Tropical Diseases from 1 October 2021 and 20 October 2021. We selected the participants who have been directly involved in diagnosing, treating, or providing nursing care to patients with COVID-19. The primary data was collected via sending the invitation directly to the participants, utilizing structured self-completed questionnaires. The seven-item fear of COVID-19 scale was used to measure the data. The responses of 208 hospital healthcare workers were included in the final analysis. (3) Results: Total score of COVID-19 fear was 19.62 (SD = 5.22). The COVID-19 fear score of 7 items ranged from 2.38 (SD = 0.83) to 3.21 (SD = 0.96). The lowest and highest scores were the item '
' and the item '
' was the highest, respectively. Linear regression of the COVID-19 fear showed that the factors positively correlated with the fear of COVID-19 among hospital healthcare workers were: being influenced by the community (
= 0.001), feeling at very high risk of COVID-19 (
= 0.03), and experiencing traumatic stress with an academic event (
= 0.042). (4) Conclusions: Although these findings merit further elaboration, these preliminary findings suggest relatively great fear of the COVID-19 pandemic among Vietnamese hospital healthcare workers and that social and personal connections are necessary for maintaining the mental wellbeing.
This paper presents the results on the fabrication of highly sensitive fluorescence biosensors for pesticide detection. The biosensors are actually constructed from the complex of quantum dots (QDs), ...acetylcholinesterase (AChE) and acetylthiocholine (ATCh). The biosensor activity is based on the change of luminescence from CdSe and CdTe QDs with pH, while the pH is changed with the hydrolysis rate of ATCh catalyzed by the enzyme AChE, whose activity is specifically inhibited by pesticides. Two kinds of QDs were used to fabricate our biosensors: (i) CdSe QDs synthesized in high-boiling non-polar organic solvent and then functionalized by shelling with two monolayers (2-ML) of ZnSe and eight monolayers (8-ML) of ZnS and finally capped with 3-mercaptopropionic acid (MPA) to become water soluble; and (ii) CdTe QDs synthesized in aqueous phase then shelled with CdS. For normal checks the fabricated biosensors could detect parathion methyl (PM) pesticide at very low contents of ppm with the threshold as low as 0.05 ppm. The dynamic range from 0.05 ppm to 1 ppm for the pesticide detection could be expandable by increasing the AChE amount in the biosensor.
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