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The purpose of this paper is to present simple correlation for calculating nitrated hydroxyl-terminated polybutadiene (NHTPB) enthalpy of formation.

It uses multiple linear regression methods.

The proposed correlation has determination coefficient 0.96. The correlation has root mean square deviation and the average absolute deviations values 53.4 and 46.1 respectively.

The predictive power of correlation is checked by cross-validation method (R²=0.96, Q L O O 2 = 0.96).

This research is an empirical study that addresses whether knowledge resources impact on, or do not impact on, innovation development and if this impact is mediated by dynamic capabilities in the medical tourism sector in Mashhad city, Iran.

A quantitative research methodology was applied and questionnaires were used for data collection in this study. A total of 108 questionnaires were collected of which 102 questionnaires were valid. Data were analyzed using structural equation modelling technique.

Empirical evidence obtained from the study reveals that the dynamic capability of learning plays a significant role in transforming knowledge resources into innovation in the medical tourism sector. The mediating role of coordinating capability in the relationship between explicit and tacit knowledge and innovation is considerable and it influences human capital, as well. Sensing capability also exhibits some degree of a mediating role; however, integrating capability is not influential and its role in transforming explicit knowledge to innovation is rejected.

Most studies on innovation in medical tourism focused on market and its typology, and neglected the role of knowledge resources and dynamic capabilities. The current study bridges this gap and thus contributes to the scientific literature.

The purpose of this study was to evaluate the association of empirically derived dietary patterns with hypertension and hyperlipidemia among a large sample of Iranian industrial employees.

This cross-sectional study was done under the framework of Epidemiological Survey of Chronic Diseases on Manufacturing Employees. Major dietary patterns were derived based on a validated short form of food frequency questionnaire (FFQ) using exploratory factor analysis. Self-administered validated questionnaires were used to collect data on socio-demographic and job-related variables of participants. Multivariable logistic regression was applied for association analyses.

Higher levels of Western dietary pattern increased significantly the risk of hypertension (odds ratio [OR] = 1.85, 95% CI [1.36-2.53], P trend <0.001) and hyperlipidemia (OR = 1.45, 95% CI [1.16-1.81], p = 0.001) even after controlling for confounding variables. The traditional dietary pattern was marginally associated with a significant increase in risk of hyperlipidemia ( = 1.14, 95% CI [0.92-1.41], p = 0.084) in the fully adjusted model. However, higher levels of healthy dietary pattern were significantly associated with a decreased risk of hyperlipidemia in the final model (OR 0.80, 95% CI [0.64-0.90], p = 0.025).

To the authors’ knowledge, an association analysis between dietary patterns and major cardiovascular disease risk in workforce population over the world is scarce and has not yet been conducted among Iranian industrial employees. This study’s findings are especially relevant for the industrial workforce population because they are at high risk of other job-related risks that increase the CVD risk.

Ferrofluids are aqueous or non-aqueous solutions with colloidal particles of iron oxide nanoparticles with high magnetic characteristics. Their magnetic characteristics enable them to be controlled and manipulated when ferrofluids are exposed to magnetic fields. This study aims to inspect the features of unsteady stagnation point flow (SPF) and heat flux from the surface by incorporating ferromagnetic particles through a special kind of second-grade fluid (SGF) across a movable sheet with a nonlinear heat source/sink and magnetic field effect. The mass suction/injection and stretching/shrinking boundary conditions are also inspected to calculate the fine points of the features of multiple solutions.

The leading equations that govern the ferrofluid flow are reduced to a group of ordinary differential equations by applying similarity variables. The converted equations are numerically solved through the bvp4c solver. Afterward, study and discussion are carried out to examine the different physical parameters of the characteristics of nanofluid flow and thermal properties.

Multiple solutions are revealed to happen for situations of unsteadiness, shrinking as well as stretching sheets. Greater suction slows the separation of the boundary layers and causes the critical values to expand. The region where the multiple solutions appear is observed to expand with increasing values of the magnetic, non-Newtonian and suction parameters. Moreover, the fluid velocity significantly uplifts while the temperature declines due to the suction parameter.

The novelty of the work is to deliberate the impact of mass suction/injection on the unsteady SPF through the special second-grade ferrofluids across a movable sheet with an erratic heat source/sink. The confirmed results provide a very good consistency with the accepted papers. Previous studies have not yet fully explored the entire analysis of the proposed model.

This study aims to investigate the association between vitamin D measured in serum 25 hydroxyvitamin D [25(OH)D] and outcomes of COVID-19 patients in Bahrain. This paper hypothesized that lower serum 25(OH)D concentration in COVID 19 patients is associated with longer viral clearance time (VCT) and higher risk of admission to the intensive care unit (ICU).

This study used a retrospective cohort design of patients admitted to Salmaniya Medical Complex, Manama, Kingdom of Bahrain, from February to June 2020. This study included patients with positive, confirmed COVID-19 diagnosis made using reverse transcription-polymerase chain reaction (RT-PCR), World Health Organization diagnosis manual and local diagnostic guidelines. Primary outcome measures were: VCT measured as the time in days between the first positive RT-PCR test result and the first of two consecutive negative RT-PCR results on recovery and admission need to ICU.

A total of 450 patients were analyzed; mean age was 46.4 ± 12.4 years and 349 (78%) were men. Mean 25(OH)D concentration was 41.7 ± 23.7 nmol/L for the entire sample. Severe vitamin D deficiency (<25 nmol/L) was present in 20%, mild-to-moderate deficiency (25–50 nmol/L) in 55%, insufficiency (50 to <75 nmol/L) in 18% and sufficiency (=75 nmol/L) in 7%. The mean VCT was 12.9 ± 8.2 days. Multivariate linear regression analysis showed that severe vitamin D deficiency was associated with longer VCT, with an average of three extra days after correction for age and sex (β = 3.1; p = 0.001). Multinomial regression analysis showed that vitamin D deficiency was associated with an 83% increased risk of admission to ICU after correction for age and sex (odds ratio = 1.8; p = 0.03).

The results showed that severe vitamin D deficiency was associated with longer recovery time from COVID-19. Low serum 25(OH)D is associated with increased need for critical care in an ICU. Large-scale randomized controlled trials are necessary to further investigate the complex association between vitamin D and COVID-19 infection.