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•Successfully doped Cu into ZnO lattice to enhance its photocatalytic activity.•Cu dopant prevented recombination of photo-excited e− and h+ of the ZnO.•The Cu-ZnO exhibited excellent ...photocatalytic degradation of monocrotophos pesticide.•The optimal mole ratio of Cu/ZnO in the Cu-ZnO for degradation of monocrotophos was 3%.•The optimal pH for the photocatalytic degradation of monocrotophos was pH 7.
In the work, we successfully synthesized Cu doped ZnO materials for photocatalytic degradation of monocrotophos pesticide (MCP). The used Cu metal doped into the ZnO matrix created an intermediate band to excite electron from valence band (VB) to conduction band (CD) of the ZnO leading to increase in optical absorption, decrease in band gap as well as photocatalytic performance of the material. Hence, the synthesized photocatalyst showed intense activity for photocatalytic degradation of MCP into CO2, H2O and harmless inorganic ions even under visible radiation. We also investigated that the 3Cu-ZnO photocatalyst, which the weight ratio of Cu/ZnO was 3 wt%, showed the highest MCP degradation efficiency among these synthesized Cu-ZnO. The excess dopants tended to form CuO existing on ZnO surface. The formed CuO acted as a center for recombination of produced electrons and holes resulted in decrease in photocatalytic performance of the Cu-ZnO. Finally, we investigated that the optimal pH for the degradation of MCP by the synthesized Cu doped ZnO photocatalyst was pH 7.
Background and Aims
Recent studies have highlighted the increased risk of low bone mineral density (BMD) in adults with cardiovascular disease. However, little is known about BMD in adults with ...congenital heart disease (CHD), particularly in developing countries. We hypothesized that factors related to BMD would lead to a high prevalence of low BMD in adults with CHD. This study aimed to determine the prevalence of low BMD and its related factors in Vietnamese adults with CHD.
Methods
We conducted a cross‐sectional study of 73 adults diagnosed with CHD in Vietnam. Low BMD was classified based on their site‐specific Z‐scores and T‐scores at the posteroanterior lumbar spine and left proximal femur. Logistic regression analyses were performed to evaluate factors related to low BMD.
Results
Low BMD was confirmed in one‐third of the adults with CHD. There were trends of more bone loss in certain parts of the body than in others, with the prevalence of low BMD at the sites of the lumbar vertebrae (L1‒L4) and left proximal femur (femoral neck, trochanteric femur, and intertrochanteric area) of 43.9%, 31.8%, 28.8%, 33.3%, 8.8%, 1.5%, and 6.1%, respectively. The prevalence of low BMD in the lumbar spine was significantly higher than that in the left proximal femur (34.3% vs. 2.9%, p < 0.001). Moreover, the prevalence of low BMD was significantly higher in adults with CHD than in those without polycythemia and vitamin D deficiency (55.6% vs. 20.9%, p = 0.001 and 46.2% vs. 19.4%, p = 0.002, respectively). A stratified multivariate logistic regression analysis revealed that low BMD was associated with polycythemia (odds ratio: 4.72; 95% confidence interval: 1.64–13.58, p = 0.004).
Conclusions
Low BMD is common among adults with CHD in Vietnam and related to polycythemia.
Little is known about the quality of life (QOL) and health status of adults with congenital heart disease (CHD) in developing countries. Therefore, this study aimed to describe the QOL and health ...status of hospitalized adults with CHD in Vietnam and investigate the association between QOL and their biological-social characteristics.
A cross-sectional study was conducted with 109 adults with CHD, hospitalized in the Vietnam National Heart Institute, between June and December 2019. Validated instruments to assess QOL and health status describing patient-reported outcomes were used, including the EuroQOL-5 Dimensions-5 Level, Satisfaction with Life Scale, and Hospital Anxiety and Depression Scale.
The mean scores on the EuroQOL-descriptive system (EQ-DS) and EuroQOL visual analogue scale (EQ-VAS) were 0.792 (SD = 0.122, 95% confidence interval CI 0.769-0.815) and 66.3 (SD = 12.5, 95% CI 63.9-68.7), respectively. A total of 9.2% (n = 9) patients experienced life dissatisfaction. The prevalence of anxiety and depression were 18.7% (n = 20) and 11% (n = 12), respectively. Scores of QOL in patients aged > 30 years were lower than in those aged ≤ 30 years. Stratified multivariate logistic regression revealed that poor QOL related to being unemployed/unstable employment (OR 4.43, 95% CI 1.71-11.47, p = 0.002), life dissatisfaction associated with unmarried status (OR 4.63, 95% CI 1.2-17.86, p = 0.026), anxiety regarding unemployment/unstable employment (OR 3.88, 95% CI 1.27-11.84, p = 0.017) and complex CHD/PAH (OR 4.84, 95% CI 1.33-17.54, p = 0.016), and depression regarding unemployment/unstable employment (OR 4.63, 95% CI 1.22-17.59, p = 0.003).
Reduced QOL and elevated psychological problems were common experiences among hospitalized adults with CHD in Vietnam. Biological-social characteristics such as unmarried status, unemployment/unstable employment, and complex CHD/PAH related to poor QOL, life dissatisfaction, anxiety, and depression.
Purpose
This paper aims to investigate how the relationships between different leadership approaches and organizational learning have been examined in the literature, from which future research areas ...can be recommended.
Design/methodology/approach
This systematic literature review applies matrix method to examine major literature in leadership and organizational learning. A total of 57 peer-reviewed English publications from 45 journals were selected and analyzed.
Findings
The synthesis of these empirical studies revealed as follows: the relationship between leadership and organizational learning has been mostly quantitatively investigated in many countries and sectors; multiple leadership styles have been identified to ameliorate processes, levels and capabilities of organizational learning and transformational leadership still remains the most commonly used style; there are mediating mechanism and boundary conditions in the relationship between leadership and organizational learning.
Research limitations/implications
The literature search in this study was mainly focused on English articles only; therefore, some papers in other languages may have not been included.
Practical implications
This review offers an overall picture of the existing knowledge of organizational learning and leadership that will be fruitful for practitioners to understand and replicate these concepts.
Originality/value
There are little systematic literature reviews on the relationship between leadership and organizational learning. This paper is among the first systematic reviews to analyze how leadership has been associated with organizational learning and provide potential research directions.
PurposeThis study aims to systematically review empirical research on the relationship between organizational learning (OL) and firm performance (FP) to evaluate how far the field has ...come.Design/methodology/approachThis study follows a systematic, transparent and replicable approach suggested by Vom Brocke et al. (2009) to conduct a systematic review. A total of 52 empirical studies published over the years 1999–2019 was retrieved and analyzed.FindingsThree key themes related to the OL–FP relationship have emerged from the review. First, research on OL and FP has been quantitatively conducted in a variety of countries and sectors. Second, dimensions of OL foster both financial and non-financial performance of firms through their combinations and interactions. Third, the relationship between OL and FP is mediated by organizational innovation.Research limitations/implicationsThe literature search returned only quantitative studies on OL and FP, which was accepted within the scope of this review. Future studies are encouraged to systematically examine case studies and qualitative research on OL and FP.Practical implicationsThis review demonstrates that FP can be improved through different dimensions of OL. Based on our findings, managers wanting to enhance the performance of their firms can analyze the demand for OL and develop those OL dimensions.Originality/valueThis is among the first systematic literature reviews on OL and FP. The findings of this study also contribute to the previously scattered understanding of OL and FP.
The purpose of this paper was to investigate the periodic nonlinearity of a frequency-modulated homodyne interferometer that limits the accuracy of displacement measurements to the nanometer order. ...We considered the idea that residual amplitude modulation (RAM) and ghost/parasitic reflections, possibly caused by a pair of semi-transparent mirrors (STMs), could induce periodic errors in our interferometric system. In our experiment, we implemented a micrometer-range linear mechanical displacement measurement using two synchronized lock-in amplifiers (LIAs) whose outputs were the second and third harmonics of the interference signal. The periodic errors of amplitude and phase were found by least-squares circle (LSC) fitting and subtraction via a polynomial fit, respectively. We clarified the existence of the periodic nonlinearity error of
λ
/4 caused by RAM generated by injection current modulation of an external cavity laser diode (ECLD). The experimental results showed that both methods determined a p–p periodic error amplitude of ~± 10 nm for the interferometer. The obtained periodic error components of
λ
/2,
λ
/4, and
λ
/8 were 5 nm rms or less over a linear displacement length of 1.5 μm, corresponding to relative periodic errors of 0.33% or less. Both methods give a good agreement within the calculated estimation, accepting the reliability of our results.
PurposeThis study aims to investigate the effects of leadership competences (cognitive, interpersonal, and results-oriented competences) on organizational learning, organizational innovation, and ...business performance.Design/methodology/approachData were collected from owners, chief executive officers, top and middle management teams, and other managers of tourism and hospitality firms in Vietnam. A total of 638 valid responses was collected and processed using PLS-SEM technique.FindingsThe findings revealed that only results-oriented competence exerted significant influences on business performance. Organizational learning was affected by all three leadership competences, while only cognitive and interpersonal competences positively affected organizational innovation. The relationships among organizational learning, organizational innovation, and business performance were also confirmed. Moreover, the findings emphasized the mediating roles of organizational learning and organizational innovation in the relationship between leadership competences and business performance. Organizational learning and organizational innovation also acted as a mediator in the relationship between cognitive competence and business performance.Practical implicationsThis study provided some suggestions for tourism and hospitality leaders in exhibiting appropriate leadership competences, strengthening organizational learning, and fostering organization innovation to enhance business performance.Originality/valueAlthough the topics of leadership competences, organizational learning, organization innovation, and business performance have received a great concern among worldwide academia, there is scarce research examining the relationships among these four phenomena together. This paper is among the first study that offers a comprehensive model of the relationships among these domains.
In the study, we successfully decorated MnFe2O4 on BiVO4 to highly improve its photocatalytic activity for degradation of tetracycline as well as its magnetically recovery. The decoration of MnFe2O4 ...on BiVO4 led to formation of MnFe2O4/BiVO4 Z scheme heterojunction to effectively prevent the charge recombination in each material. Upon visible light, the MnFe2O4/BiVO4 heterojunction produced significant available amounts of e− and h+ existing in the conduction band of the MnFe2O4 and the valence band of the BiVO4, respectively. These produced e− on the conduction band of the MnFe2O4, which reduction potential was approximately −0.41 eV, exhibited strong reduction potential reducing oxygen to produce •O2− radicals while h+ on the valence band of the BiVO4, which oxidation potential was 2.77 eV, showed strong oxidation potential oxidizing water and hydroxyl groups to produce •OH radicals. These generated active oxygen radicals effectively degraded TC in water (~92%). The used photocatalysts were easily recovered from photocatalytic suspension using an external magnet due to high magnetically activity of the MnFe2O4, which tightly bonded with BiVO4 in the MnFe2O4/BiVO4 heterojunction. Finally, the recovered MnFe2O4/BiVO4 heterojunction was very active and stable for tetracycline degradation in long-term process.
FeO‐doped TiO2 nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol‐gel process. As an adsorbent and photocatalyst, FeO‐TiO2 on immobilized ACFs ...(FeO‐TiO2/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO2 and ACF‐TiO2 under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons‐hole recombination, thereby promoting the photocatalysis action of doped photo‐metal oxides of FeO‐TiO2. Co‐doping of FeO onto the lattice of the TiO2 approach can improve the absorption activity of visible light through photo‐metal oxide of TiO2 and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO‐TiO2/ACF) were effortlessly split out from the experimental solution for re‐utilization and exhibited high stability even after five complete regeneration cycles.
Hydrogen production and stability of catalytic materials still suffer from low efficiency due to the fast rate of recombination of electron‐holes in the photocatalytic process. Fibrous activated carbon (ACF) served as surface immobilizer to capture co‐doped FeO/TiO2 for improving the sorption of a nanocatalyst onto the porous surface. Stable FeO/TiO2 nanoparticles were immobilized on the ACF surface.
In this study, titanium (Ti) was used as an active dopant to incorporate into BiVO4 lattice using the hydrothermal method. The synthesized BiVO4 and Ti–BiVO4 with 1, 5 and 10 wt% of Ti dopants have ...been applied for photocatalytic decomposition of Tetracycline under visible light irradiation. The characterized results showed that this synthesized BiVO4 and Ti–BiVO4 materials existed in a form of spherical particles. The particle sizes of the Ti–BiVO4 were much bigger than that of the BiVO4. However, Ti dopants effectively enhanced visible light absorption, decreased band gap energy as well as prevented electron-hole recombination of the BiVO4 leading to increase in photocatalytic activities of the doped materials. The obtained results from photocatalytic experiments indicated that the 5Ti–BiVO4, whose weight ratio of Ti was 5%, was the best material for TC degradation (78.49%). Recycling tests were consecutively carried out in 4 runs to demonstrate the stability of the BiVO4 photocatalyst with 5 wt% of Ti dopant.
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