An ultra melt-resistant hydrogel from food grade carbohydrates

© 2017 The Royal Society of Chemistry. We report a binary hydrogel system made from two food grade biopolymers, agar and methylcellulose (agar-MC), which does not require addition of salt for gelation to occur and has very unusual rheological and thermal properties. It is found that the storage modulus of the agar-MC hydrogel far exceeds those of hydrogels from the individual components. In addition, the agar-MC hydrogel has enhanced mechanical properties over the temperature range 25-85 °C and a maximum storage modulus at 55 °C when the concentration of methylcellulose was 0.75% w/v or higher. This is explained by a sol-gel phase transition of the methylcellulose upon heating as supported by differential scanning calorimetry (DSC) measurements. Above the melting point of agar, the storage modulus of agar-MC hydrogel decreases but is still an elastic hydrogel with mechanical properties dominated by the MC gelation. By varying the mixing ratio of the two polymers, agar and MC, it was possible to engineer a food grade hydrogel of controlled mechanical properties and thermal response. SEM imaging of flash-frozen and freeze-dried samples revealed that the agar-MC hydrogel contains two different types of heterogeneous regions of distinct microstructures. The latter was also tested for its stability towards heat treatment which showed that upon heating to temperatures above 120 °C its structure was retained without melting. The produced highly thermally stable hydrogel shows melt resistance which may find application in high temperature food processing and materials templating

Linking medical faculty stress/burnout to willingness to implement medical school curriculum change: a preliminary investigation

Rationale, aims and objectivesBalancing administrative demands from the medical school while providing patient support and seeking academic advancement can cause personal hardship that ranges from high stress to clinically recognizable conditions such as burnout. Regarding the importance of clinical faculties’ burnout and its effects on different aspects of their professional career, this study was conducted and aimed to evaluate the relationship between willingness to change teaching approaches as characterized by a modified stage‐of‐change model and measures of stress and burnout.MethodsThis descriptive analytic study was conducted on 143 clinical faculty members of Tehran University of Medical Sciences in Iran. Participants were asked to complete three questionnaires: a modified stages of change questionnaire the Maslach Burnout Inventory and the General Health Questionnaire. Data were analysed by SPSS: 16 using non‐parametric statistical tests such as multiple regression and ICC (intra‐class coefficient) and Spearman correlation coefficient test.ResultA significant relationship was found between faculty members’ readiness to change teaching approaches and the subscales of occupational burnout. Specifically, participants with low occupational burnout were more likely to be in the action stage, while those with high burnout were in the attitude or intention stage, which could be understood as not being ready to implement change. There was no significant correlation between general health scores and stage of change. ConclusionsWe found it feasible to measure stages of change as well as stress/burnout in academic doctors. Occupational burnout directly reduces the readiness to change. To have successful academic reform in medical schools, it therefore would be beneficial to assess and manage occupational burnout among clinical faculty members.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135679/1/jep12439.pd

Optical spectroscopy and X-ray observations of the D-type symbiotic star EF Aql

We performed high-resolution optical spectroscopy and X-ray observations of the recently identified Mira-type symbiotic star EF Aql. Based on high-resolution optical spectroscopy obtained with SALT, we determine the temperature ($\sim$55 000 K) and the luminosity ($\sim$ 5.3 $L_\odot$) of the hot component in the system. The heliocentric radial velocities of the emission lines in the spectra reveal possible stratification of the chemical elements. We also estimate the mass-loss rate of the Mira donor star. Our Swift observation did not detect EF Aql in X-rays. The upper limit of the X-ray observations is 10$^{-12}$ erg cm$^{-2}$ s$^{-1}$, which means that EF Aql is consistent with the faintest X-ray systems detected so far. Otherwise we detected it with the UVOT instrument with an average UVM2 magnitude of 14.05. During the exposure, EF Aql became approximately 0.2 UVM2 magnitudes fainter. The periodogram analysis of the V-band data reveals an improved period of 320.4$\pm$0.3 d caused by the pulsations of the Mira-type donor star. The spectra are available upon request from the authors.Comment: Accepted for publication in MNRA

Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads

This journal is © The Royal Society of Chemistry. We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a slurry of hydrogel microbeads. The pancake batter was mixed with a controlled volume percentage of slurry of hydrogel beads and cooked. From bomb calorimetry experiments, the composites were found to have a reduced caloric density that reflects the volume percentage of hydrogel beads mixed with the batter. Using this procedure, we were able to reduce the caloric density of pancakes by up to 23 ± 3% when the volume percentage of hydrogel beads initially used was 25%. The method is not limited to pancakes and could potentially be applied to various other food products. The structure and morphology of the freeze-dried pancakes and pancake-hydrogel composites were investigated and pores of a similar size to the hydrogel beads were found, confirming that the gel beads maintained their structure during the cooking process. There is scope for further development of this method by the encapsulation of nutritionally beneficial or flavour enhancing ingredients within the hydrogel beads