This paper presents an analytical approach to investigate the buckling and postbuckling behavior of functionally graded cylindrical shells subjected to thermal and axial compressive loads. Material ...properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of constituents. The governing equations are established within the framework of classical thin shallow shell theory taking both geometrical nonlinearity in von Kármán–Donnell sense and initial imperfection into consideration. Thermal stability analysis also incorporates the effects of tangential edge constraints. A Galerkin procedure is applied to derive expressions of load-deflection relations from which the thermal buckling loads and postbuckling curves of the shells are obtained by an iteration. Effects played by material and geometrical properties, tangential stiffness, imperfection and buckling modes are discussed.
Methadone, a long-acting opioid agonist maintenance treatment (MMT) is used to treat opioid addiction by preventing opioid withdrawal and reducing cravings. However, it is important to note that ...mental conditions may persist, or even remain undetected while methadone maintenance treatment is ongoing. This study aimed to examine the level of psychological problems among MMT patients at public and private health facilities and identify associated factors.
From January to September 2018, a cross-sectional study was performed in Nam Dinh province, one of the largest epicenters providing HIV/AIDS surveillance and treatment services in the North of Vietnam. 395 male respondents currently receiving MMT agreed to participate in a face-to-face interview. Depression, Anxiety and Stress Scale-21 (DASS-21) were used to assess psychological problems among patients.
The percentage of patients suffering from mild to extremely severe anxiety was the highest among psychological problems (18%). 2.8% of participants had mild depressive symptoms and the percentage of those having mild or moderate stress was approximately 4%. In addition, the longer treatment duration, the lower mental health scores regarding three types of psychological problems. Respondents who received MMT services in public health facilities were more likely to have a higher score of all psychological problems. Participants who lived with partners or spouse, having higher monthly family income had a lower likelihood of having severe depression and stress status. Freelancers or blue-collars/farmers had lower score of depression and anxiety compared to people being unemployed.
This study suggests that among our sample, MMT patients receiving treatment in public health facilities might have higher rate of psychological problems, including depression, anxiety, and stress than that of those in the private health facility. These results highlight the necessity of taking psychological counseling adequately for MMT patients and psychological assessment should be prioritized in the early stage of treatment.
This paper deals with the nonlinear free vibration of carbon nanotube (CNT)-reinforced composite cylindrical panels exposed to thermal environments. All boundary edges are assumed to be simply ...supported and tangentially restrained. CNTs are reinforced into isotropic matrix in such a way that their volume is uniform or varied across the thickness direction according to functional rules. In order to capture size effects, the effective properties of CNT-reinforced composite are estimated using an extended version of linear rule of mixture. Motion and compatibility equations are established within the framework of classical shell theory including von Kármán–Donnell nonlinearity, initial geometric imperfection and interactive pressure from elastic foundations. Analytical solutions are assumed, and Galerkin procedure is applied to derive a time differential equation containing quadratic and cubic nonlinear terms. Fourth-order Runge–Kutta integration scheme is employed to determine the frequencies of nonlinear vibration of the panels. Through a parametric study, numerous influences of CNT distribution, size of imperfection, degree of in-plane edge constraint, foundation stiffness and elevated temperature on the natural frequencies and nonlinear-to-linear frequency ratio are analyzed.
Statins and omega-3 supplementation have been recommended for cardiovascular disease prevention, but comparative effects have not been investigated. This study aimed to summarize current evidence of ...the effect of statins and omega-3 supplementation on cardiovascular events. A meta-analysis and a network meta-analysis of 63 randomized controlled trials were used to calculate pooled relative risks (RRs) and 95% confidence intervals (CIs) for the effects of specific statins and omega-3 supplementation compared with controls. Overall, the statin group showed significant risk reductions in total cardiovascular disease, coronary heart disease, myocardial infarction, and stroke; however, omega-3 supplementation significantly decreased the risks of coronary heart disease and myocardial infarction only, in the comparison with the control group. In comparison with omega-3 supplementation, pravastatin significantly reduced the risks of total cardiovascular disease (RR = 0.81, 95% CI = 0.72-0.91), coronary heart disease (RR = 0.75, 95% CI = 0.60-0.94), and myocardial infarction (RR = 0.71, 95% CI = 0.55-0.94). Risks of total cardiovascular disease, coronary heart disease, myocardial infarction, and stroke in the atorvastatin group were statistically lower than those in the omega-3 group, with RRs (95% CIs) of 0.80 (0.73-0.88), 0.64 (0.50-0.82), 0.75 (0.60-0.93), and 0.81 (0.66-0.99), respectively. The findings of this study suggest that pravastatin and atorvastatin may be more beneficial than omega-3 supplementation in reducing the risk of total cardiovascular disease, coronary heart disease, and myocardial infarction.
This paper investigates the buckling and postbuckling of nearly cylindrical shell (NCS) made of functionally graded porous material (FGPM) and subjected to external lateral pressure (ELP) in thermal ...environments. The variation of two material constituents through the shell thickness is modelled by a power-law distribution. Porosities are assumed to distribute into FGPM according to forms of cosine functions. Basic equations in terms of deflection and stress function are established within the framework of classical shell theory taking into account von Kármán - Donnell nonlinearity. Boundary edges of the NCS are assumed to be simply supported and tangentially restrained. Multi-term analytical solutions are assumed and Galerkin method is used to derive expressions of buckling loads and nonlinear load-deflection relation. Parametric studies are carried out to assess the effects of coefficient and distribution type of porosity, thermal environments, geometry properties and in-plane boundary condition on the critical loads and postbuckling strength of pressure-loaded FGPM NCSs.
Background Traumatic brain injury (TBI) is a leading cause of mortality and morbidity globally. This study aimed to measure the health-related quality of life (HRQOL) of TBI patients in Vietnam and ...evaluate the associated factors. Methods A longitudinal study was conducted in Thai Binh, Vietnam, from February to September 2020. The EuroQol-5 Dimensions-5 Levels (EQ-5D-5L) and EQ-Visual Analog Scale (EQ-VAS) were used to measure HRQOL. Socio-demographic characteristics, including age, gender, education level, employment status, marital status, and income, as well as clinical characteristics such as injury severity, cause of injury, comorbidities, and functional status, were collected through patient interviews and medical records. Multivariate Tobit regression analysis was performed to identify variables associated with HRQOL. Results The study included 212 TBI patients. The mean scores of the VAS and EQ-5D-5L scales were 82.4/100 (SD = 14.49) and 0.9/1.0 (SD = 0.2), respectively, indicating a relatively high HRQOL. However, certain factors significantly impacted HRQOL. Unemployed patients and those with depression or higher injury severity, as measured by the Injury Severity Score (ISS), had notably lower HRQOL scores. Poor sleep quality and severe functional impairments also adversely affected HRQOL, whereas patients discharged for a longer period had slightly better HRQOL scores. Conclusion This study highlights that while HRQOL is relatively high among TBI patients, mental health disorders, injury severity, and functional impairments are key factors negatively impacting their quality of life. High HRQOL was defined by mean scores on the VAS and EQ-5D-5L scales, with higher scores indicating better quality of life. Home-based interventions addressing these issues could improve HRQOL for TBI patients.
This study is among the first studies investigating how non-given attributes are used in deciding stated choices for daily travel under anchoring perspective. Our theoretical work leads us to a ...conceptual model that non-given attributes are systematically included in the choice making process based on their relevance to the choice decision. The relevant rule for re-packing of the attribute set is activated in a way that the involvement of non-given attributes does not eliminate the influence of given attributes on choices. Notably, more non-given attributes are involved in choice decision when respondents deal with cases that are more difficult to trade-off between given attributes. To obtain empirical supports, a paper-based questionnaire interview was conducted. Findings based on 649 individual responses of travellers in Can Tho city, Vietnam successfully showed that travel time and travel cost significantly influence the stated choice between bus and motorcycle regardless of the involvement of respondents’ travel experiences. In addition, it was observed that all the investigated travel experiences were associated with stated choices in more difficult cases (more efforts to trade-off between travel time and travel cost) while fewer travel experiences were associated with stated choices in less difficult cases (less efforts to trade-off between travel time and travel cost). The positive association between the judgement difficulty based on given attributes and the number of anchors associated with stated choices suggests that the search engine of respondents is task-dependent and it tends to expand its searching scope accordingly to the task difficulty. This implies that the anchoring effect is more complicated in more difficult cases, and that stated scenarios are not equally treated by respondents. As such, any conclusion of stated choices should be made in full awareness of this important phenomenon.
The large‐amplitude vibration of initially stressed functionally graded material (FGM) rectangular plates with porosities is investigated in this paper. All edges of the plate are simply supported ...and uncompressed edges are tangentially restrained. Initial stresses are caused by in‐plane compressive load acting on freely movable edges or thermally induced forces at restrained edges. Pores present in FGM through even and uneven distributions. Material properties are assumed to be temperature‐dependent and, due to the presence of the pores, the effective properties of FGM are determined using a modified rule of mixture. Governing equations in terms of deflection and stress function are established based on the classical plate theory taking into account von Kármán nonlinearity and initial geometric imperfection. These equations are solved using approximate analytical solutions along with the Galerkin method to obtain a time differential equation containing quadratic and cubic nonlinear terms. Nonlinear frequencies are determined by means of numerical integration employing the fourth‐order Runge–Kutta scheme. Parametric studies are carried out to analyze the effects of material and geometry properties, porosity volume fraction and distribution, pre‐existent compressive and thermal loads, imperfection and degree of tangential constraints of unloaded edges on the natural frequencies and nonlinear to linear frequency ratio of FGM plates.
The large‐amplitude vibration of initially stressed functionally graded material (FGM) rectangular plates with porosities is investigated in this paper. All edges of the plate are simply supported and uncompressed edges are tangentially restrained. Initial stresses are caused by in‐plane compressive load acting on freely movable edges or thermally induced forces at restrained edges. Pores present in FGM through even and uneven distributions. Material properties are assumed to be temperature‐dependent and, due to the presence of the pores, the effective properties of FGM are determined using a modified rule of mixture.…
This paper addresses a soil bio-stabilization technique using bacterial enzyme-induced calcium carbonate precipitation (BEICP) as an alternative to previous conventional methods including ...microbial-induced carbonate precipitation and plant-derived enzyme-induced carbonate precipitation. The extracted urease enzyme of viable
S. pasteurii
was used as a biological source along with calcium chloride and urea to solidify sandy soil and silty sand soil. The bio-treated soil columns were subjected to freeze and thaw (
F
–
T
) cycling for a durability evaluation. Engineering properties of bio-cemented soil including unconfined compressive strength, calcium carbonate contents, moisture contents, porosity, permeability, and microstructure were examined before and after the
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T
durations. It was found that although bio-stabilizer was able to increase a frost duration of soil, the
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cycling significantly impacted on the compressive strength of bio-treated soil, due to a formation of microcracks. This investigation has revealed that the BEICP method provided a similar capacity in
F
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resistance of soil as using the traditional Portland cement stabilizer, whereas the class
F
fly ash did not improve
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durability of medium dense soil.
Background: Childhood obesity has become a major global epidemic that causes substantial social and health burdens worldwide. The effectiveness of childhood obesity control and prevention depends ...largely on understanding the issue, including its current development and associated factors in a contextualized perspective. Objectives: Our study aimed to gauge this kind of understanding. Methods: We systematically searched the Web of Science database for studies concerning child obesity published up to 2017 and analyzed the volume of publications, growth rates, impact scores, collaborations, authors, affiliations, and journals. A total of 57,444 research papers were included. Results: The three subject categories with the highest number of papers (over 3,000) were (1) nutrition and dietetics, (2) pediatrics, and (3) public, environmental, and occupational health. We found a dramatic increase in the amount of scientific literature on childhood obesity in the past one or two decades, led by scholars from the USA – ranking at the top regarding the total number of papers (23,965 papers; 30.8%) and total number of citations (859,793 citations) – and multiple Western countries where the obesity epidemic is prevalent. Conclusions: The findings highlight the need for improving international and local research capacities and collaboration to accelerate knowledge production and translation into contextualized and effective childhood obesity prevention.
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