Structural and magnetic properties of isovalently substituted multiferroic BiFeO3: Insights from Raman spectroscopy

Raman spectra, supplemented by powder x-ray diffraction and magnetization data of isovalently A- and B-site substituted BiFeO3 in the Bi1−xLaxFeO3 (0≤x≤1), Bi1−xTbxFeO3 (0≤x≤0.2), and Bi0.9Sm0.1Fe1−xMnxO3 (0≤x≤0.3) series, are presented. A good agreement between the structural transitions observed by x-ray diffraction and the vibrational modes observed in the Raman spectra is found over the whole substitutional ranges, and in particular we find spectroscopic signatures of a PbZrO3-type structure for Bi0.8La0.2FeO3. Mode assignments in the substituted materials are made based on Raman spectra of the end-members BiFeO3 and LaFeO3. Moreover, by comparing spectra from all samples with R3c structure, the phonon assignment in BiFeO3 is revisited. A close connection between the degree of octahedral tilt and the Raman shift of the A1 oxygen a−a−a− tilt mode is established. An explanation for the strong second-order scattering observed in Bi1−xLaxFeO3 and Bi1−xTbxFeO3 is suggested, including the assignment of the previously mysterious BiFeO3 mode at 620 cm−1. Finally, the magnetization data indicates a transition from a cycloidal modulated state towards a canted antiferromagnet with increasing A-site substitution, while Bi0.9Sm0.1Fe1−xMnxO3 with x=0 and 0.15 exhibit an anomalous closing of the hysteresis loop at low temperatures. For low A-site substitution levels (x≤0.1) the decreasing Raman intensity of the Fe derived modes correlates with the partial destruction of the spin cycloid as the substitution level increases

Fractal modeling of moisture diffusion in wood

The mechanisms of moisture diffusion in wood are not yet fully understood, due to the complex and hierarchical structure of the wood cell wall constituents. In order to investigate this mechanism in this hierarchical structure, fractal geometry analysis was used as proper tool. This study has three major objectives: first, to investigate and understand water sorption, pore structure, and fractal property of two softwood and two hardwood species; second, to develop a theoretical fractal moisture diffusion model for wood cell wall by taking into consideration its structural geometry using the tortuous capillary bundle model and fractal theory; and third, to upscale that model to gross wood by employing electrical resistance modeling and validation. The proposed fractal diffusion model is a function of both pore and tortuosity fractal dimensions, porosity, and pore size distribution of the wood cell wall. The water vapor sorption behaviors of various wood types were studied using the dynamic sorption method. Their pore structure and fractal characteristics were investigated using nitrogen and mercury intrusion porosimetry. The pore size distribution ranged from 1.4 nm to 350 um, and porosity ranged between 58 and 76 %. The pore and tortuous fractal dimension values ranged from 2.5 to 2.98, and from 1.034 to 1.076, respectively, with a higher degree of pore complexity for larger pores. The derived fractal diffusion model was validated using experimental and data calculated by a past published model. The trends for diffusion coefficients predicted by the fractal model were similar to the experimental and calculated data and successfully predicted the diffusion coefficients at low moisture contents. Pore size ratio, pore, and tortuous fractal dimensions were negatively correlated to fractal diffusivity, while the porosity was positively correlated. When the pore and tortuosity fractal dimensions were close to 2 and 1, respectively, the diffusion coefficient values approached to the minimum. The findings of this study contribute to the creation of a decision support system that would allow predicting wood geometric properties and moisture diffusivity properties based on wood structural and ultrastructural attributes.Forestry, Faculty ofGraduat

Adherence to anti-asthma medications among adult asthmatic patients in Eastern Ethiopia: A multi-center cross-sectional study

Introduction Adherence to anti-asthmatic medications plays a vital role in enhancing an asthma patient’s quality of life and prognosis. However, in Ethiopia, the level of adherence and contributing factors were rarely studied. Therefore, this study was conducted to determine the level of adherence to anti-asthma medications and associated factors among adult asthmatic patients in Eastern Ethiopia. Method Institutional based cross-sectional study was conducted at six governmental hospitals found in Eastern Ethiopia. A total of 320 asthma patients aged 18 years and above and using asthma medicines for at least 12 months were involved. An interviewer based structured questionnaires were used to collect the data. Bivariable and multivariable logistic regression analyses were carried out using IBM SPSS version 22 (SPSS, Chicago, IL). The Adjusted Odds Ratio (AOR) with 95% Confidence Interval (CI) was used to determine the strength of association between independent variables and outcome variable. Variables with a p-value of ≤ 0.05 were considered statistically significant. Result Of the 320 asthma patients that participated in the study, 109(34.1%:28.8–39.1%) of them had good adherence to anti-asthmatic medications. Being a housewife (AOR = 4.265, 95%CI: 1.333, 13.653), having good knowledge about asthma (AOR = 2.921, 95%CI (1.472, 5.795), positive attitude towards asthma (AOR = 3.129, 95%CI: 1.555, 6.293), and use of oral corticosteroid drugs (AOR = 1.967, 95%CI: 1.008, 3.841) were factors positively associated with good adherence to anti-asthmatic medications. Participants on treatment for 2–3 years (AOR = .295, 95%CI: 0.099, 0.873), and those on medication for ≥ 4 years (AOR = 0.229, 95%CI: 0.079, 0.664) were 70.5% and 77.1% times less likely to adhere to anti-asthmatic medications respectively. Conclusion The current study signified a low level of adherence to anti-asthmatic medications. Participant’s characteristics and medication related factors were significantly associated with good adherence to anti-asthmatic medications. Health education and advice during follow-up for asthma patients is crucial for better adherence

Triggering factors of asthma among study participants.

Note; Others: perfume, aspirin, certain food, work related trigger (working in industry), and beta-blockers.</p

Socio-demographic characteristics of study participants.

Socio-demographic characteristics of study participants.</p

Factors associated with adherence to anti-asthmatic medications among study participants.

Factors associated with adherence to anti-asthmatic medications among study participants.</p

Type of medications used by study participants.

Note; SABA: Short Acting Beta2 Agonist, ICS; Inhaled Corticosteroid, OCS; Oral Corticosteroid, LABA; long acting Beta2 Agonist.</p

S1 Data -

(SAV)</p

Patient related characteristics of study participants.

Patient related characteristics of study participants.</p

Disease related factors among study participants.

Disease related factors among study participants.</p