Fano-like resonance from disorder correlation in vacancy-doped photonic crystals

By preparing colloidal crystals with random missing scatterers, crystals are created where disorder is embodied as vacancies in an otherwise perfect lattice. In this special system, there is a critical defect concentration where light propagation undergoes a transition from an all but perfect reflector (for the spectral range defined by the Bragg condition), to a metamaterial exhibiting an enhanced transmission phenomenon. It is shown that this behavior can be phenomenologically described in terms of Fano-like resonances. The results show that the Fano's parameter q experiences a sign change signaling the transition from a perfect crystal exhibiting a reflectance Bragg peak, through a state where background scattering is maximum and Bragg reflectance reaches a minimum to a point where the system reenters a low scattering state recovering ordinary Bragg diffraction. A simple dipolar model considering the correlation between scatterers and vacancies is proposed and the reported evolution of the Fano-like scattering is explained in terms of the emerging covariance between the optical paths and polarizabilities and the effect of field enhancement in photonic crystal (PhC) defectsPID2021-124814NB-C21, PGC2018-095777-B-C22, PID2019-109905GA-C22, CEX2018-000805-M, UAM-CAM project (SI1/PJI/2019-00052

Effect of Mesenchymal Stem Cells and Chicken Embryo Extract on Flap Viability and Mast Cells in Rat Skin Flaps

Study Objective: We investigated the effect of bone marrow mesenchymal stem cells (BMMSCs) and chicken embryo extract (CEE), alone and in combination, on tissue viability of skin flaps, and mast cells (MCs), in an experimental random skin flap (RSF) rat model. Materials and Methods: A 30 mm × 80 mm RSF was made on the dorsum of each of the forty rats, which were then divided into four groups. One group did not receive any treatment and served as the control, the second group received BMMSCs, the third group received CEE + BMMSCs, and the fourth group received CEE. For BMMSC treatment, 6 × 109 BMMSCs were injected into twelve separate injection sites of each flap. Seven days after RSF surgery, the remaining viable part of each flap was measured and examined to determine the number of blood vessels, MCs, and degranulated MCs. Results: The CEE, CEE + BMMSC, and BMMSC groups displayed significantly higher levels of flap viability (ANOVA test: p = 0.000; LSD test for all groups: p = 0.000), and a greater number of vessels (ANOVA test: p = 0.000; LSD test: p = 0.000, 0.002, and 0.012, respectively), compared with the control group. The flap viability was poorer in the BMMSC group than in the CEE and CEE + BMMSC groups. The BMMSC group also had a greater number of degranulated and total MCs, compared with the CEE and CEE + BMMSC groups. Conclusions: We observed biostimulatory effects of BMMSCs, CEE, and CEE + BMMSCs on flap viability and vessel numbers, compared to the control group. MCs produced in response to BMMSC treatment have an inhibitory effect on the RSFs survival in an ischemic tissue model

Aerobic Exercise-Assisted Cardiac Regeneration by Inhibiting Tryptase Release in Mast Cells after Myocardial Infarction

Background. Cardiovascular disease (CVD) contributes critically to the mortality, morbidity, and economic problem of illness globally. Exercise is a share of everyone’s life. Some evidence-based studies have frequently shown a progressive correlation between physical activity and good health. Objective. The effects of daily exercise on cardiomyocyte size, collagen content (fibrosis), and releasing mast cells (MCsʼ) tryptase of the model of myocardial infarction (MI) were assessed. Methods. 40 rats were coincidentally spread into sham+inertia (control), sham+exercise, infarction+inertia, and infarction+exercise groups. An experimental model of acute MI was induced in infarction groups. One week after surgery, exercising groups were allowed to an aerobic exercise program for six weeks. At the endpoint of the study, all examinations were performed. Results. We found lesser fibrosis in sham+exercise and infarction+exercise groups compared to sham+inertia and infarction+inertia groups, respectively (p=0.023, p=0.001). Also, infarction groups were significantly lower than sham groups (p<0.05) and the infarction+exercise group was significantly lower than the infarction+inertia group (p<0.05). The effect of exercise on MCs while increased MC density and degranulation occur at the site of fibrosis, we demonstrated that exercise decreases both total MC density and degranulation in both sham and infarction groups (p<0.05). Immunohistochemistry examinations were significantly higher expression of MCsʼ tryptase in infarction groups than sham groups (p<0.05, p<0.0001). Conclusion. Exercise improves fibrosis and cardiac function in both healthy and MI rats by inhibiting released MCsʼ tryptase

Assessing critical thinking of postgraduate students

The purpose of this research is to check reliability of a non standard test for measuring two skills of critical thinking. We compared the result of this study with that was performed with WGCTA-SF as a common standard test for measuring the critical thinking skills

Designing externally controllable optical filters with two-dimensional magnetized plasma photonic crystals

This study proposes a two-dimensional plasma photonic crystal structure to design a tunable optical filter by changing the plasma characteristics or applying an external magnetic field. The structure is composed of two-dimensional arrays of dielectric rods with a radius of b which is defected by a row of plasma rods with a radius of b/2 in the middle of the structure. The optical properties of the structure are simulated using the finite-difference time-domain (FDTD) method. The results indicate that with the rise in the electron density of the plasma rods and changes in the intensity and direction of the applied magnetic field, which is externally controllable, the appeared defect mode in the photonic bandgap, for a TE (Transverse Electric) polarized incident electromagnetic beam, can be easily modulated. This ability suggests that the proposed structure is a good candidate for designing externally tunable optical filters which have a lot of applications

Assessment of Dental Care and its Related Barriers in Pregnant Women of Hamadan City

Background and Objectives: Oral health behaviors of pregnant women are important due to their effects on mother and child’s health. The objective of this study was to investigate dental care and its related barriers among pregnant women in Hamadan city, Iran. Materials and Methods: This cross-sectional study was carried out on 280 pregnant women in Hamadan city in 2012. We used stratified cluster sampling to select the subjects and a researcher-made questionnaire was used. The questionnaire included demographic information, common dental problems, visit of a dentist during pregnancy and tooth brushing, as well as the perceived barriers of these two behaviors. The reliability and validity of the tool were evaluated using estimates of internal consistency and the opinions of a panel of experts, respectively. Data were analyzed in SPSS-16 using logistic regression test. Results: The mean age of pregnant women was 27.2 ± 4.88 years. Tooth brushing after each meal and use of mouthwash rates were 12% and 20%, respectively. Half of the participants had not seen a dentist during their current pregnancy. The most important barriers to brush twice a day were impatience and lack of energy. Dental visit barriers were cost, low priority, and stress related to dentistry. Factors associated with no dental visit included poor economic status (P= 0.011) and working outside of home (P= 0.045). Conclusions: Given the important adverse outcomes associated with poor oral health on mothers and babies, interventions to reduce the barriers of dental cares are crucial