Guest editorial: special issue on bone tissue engineering

No abstract availabl

Examination of Silica Sol-Gels and Aerogels Containing Silver Nanoparticles and 4-Mercaptobenzoic Acid Using Surface-Enhanced Raman Spectroscopy

Sol-gels and aero-gels containing silver nanoparticles have been investigated for use as substrates in surface-enhanced Raman spectroscopy (SERS). 4-Mercaptobenzoic acid (4-MBA) was chosen as the target molecule in this study, as it has been well-characterized using SERS. The orientation of the 4-MBA at different coverages in gels, and at differing concentrations of silver colloid, has not been well studied. For both base and acid-catalyzed sol-gels, xerogels, and aerogels, the concentration of 4-MBA was varied with a constant silver colloid concentration in the silica gels and the effects were measured with SERS. The effect of varying silver colloid concentration against a constant 4-MBA concentration was also investigated. The results of each process were compared

Nontraditional Students Success in Compressed Courses within a Community College Cohort

Nontraditional students are an untapped population for American higher education institutions. Private baccalaureate-granting universities have taken the lead on creating programs for this population’s needs. These programs typically include combinations of online instruction, cohorts, compressed or accelerated courses, and prior learning assessment. Similarly constructed programs for nontraditional students at public community colleges are less common. A review of the Council for Accelerated Programs’ website reveals only twelve of the 98-member institutions are community or technical colleges, and only one is in California (Council for Accelerated Programs, n.d.). In 2016, Shasta-Tehama-Trinity Joint Community College District in California created the Accelerated College Education (ACE) program specifically for working adults. ACE utilizes a cohort model, compressed courses, structured scheduling, and dedicated staff and faculty. However, little research exists that evaluates the combination of these elements for correlation to course success or student feelings of connectedness at a community college. This study uses Tinto’s framework of academic and social integration, including criticisms of its applicability to nontraditional students, to evaluate academic and social integration of Shasta College students who completed ACE compressed courses between June 2016 and December 2017. Course grade data showed higher participation by nontraditional students in these courses, and the ACE-cohort students’ course success rate was significantly higher than non-ACE-cohort students’ course success rate. Survey results demonstrated that ACE-cohort students had significantly more interactions with and feelings of connectedness to program/student support staff and other students than non-ACE-cohort students, and that these connections may have contributed to the success of their overall academics

The influence of calf selenium status on GPx-1 and 3 activity and liver GPx-1 mRNA

The purpose of this research was to determine the influence of dietary Se on glutathione peroxidase (GPx)-1 and 3 activities and relative liver GPx mRNA levels in growing Holstein bull calves. Calves (n = 14) were started 28 d after birth on either a Se adequate (0.15 ppm Se) or deficient (0.01 ppm Se) diet consisting of 3 growth phases and maintained on the diet until 180 d of age. Blood samples were taken from each calf for determination of GPx-1 and GPx-3 activity. Three calves were euthanized at d 21 of age for determination of baseline liver GPx-1 mRNA level. Four calves from each treatment were euthanized at d 180 of age for determination of liver GPx-1 relative mRNA level. Feed intake and average daily gain were not affected by Se level. Mean liver Se concentration was higher (P \u3c 0.05) for baseline calves and those fed the Se adequate diet than for calves fed the Se-deficient diet, but there was no difference between baseline calves and Se adequate calves with respect to liver Se concentration. The GPx-1 activity was greater for Se adequate than Se-deficient calves (P \u3c 0.01) but not until d 84 of age. The GPx-3 activity was considerably more variable than that of GPx-1 with respect to the trend observed for activity by day, and the GPx-3 activity of the Se-deficient group was only less than that of the Se adequate group (P \u3c 0.05) on d 180. N-fold differences were calculated for relative GPx-1 mRNA levels between treatments. There was a 50% decrease in GPx-1 mRNA for Se-deficient calves (P \u3c 0.05) compared with the Se adequate calves. Regression analysis also was performed to determine the relationship between the various response variables. There was only a moderate relationship (r2 = 0.58) between GPx-1 mRNA transcript levels and GPx-1 activity at d 180, despite a correlation coefficient of 0.76. The relationship between GPx-1 mRNA transcript level and GPx-3 activity at d 180 was much stronger (r2 = 0.81), with a correlation coefficient of 0.90, which was unexpected, as GPx-3 is generally considered a short-term indicator of Se status and therefore a much more variable response. Erythrocyte GPx-1 activity was much more sensitive to Se in the diet and thus reflected the diet more closely than did GPx-3. However, GPx-3 activity was more highly correlated to GPx-1 transcript levels. These unexpected results suggest that another trial utilizing larger sample sizes and serial sampling of liver tissue with the sampling of plasma and erythrocytes may provide a clearer picture of the relationship between liver GPx-1 mRNA , tissue Se concentration, and GPx enzyme activities in neonatal and growing Holstein calves

Prediction of Cardiorespiratory Fitness from Maximal Anaerobic Capacity

Incremental treadmill VO2max protocols are often considered the superior method of assessing cardiorespiratory fitness. These exercise test protocols stress aerobic energy production pathways. However, at the point of VO2max attainment anaerobic energy systems are the predominant mechanisms of adenosine triphosphate (ATP) production. Likewise, the Wingate cycle test, a commonly accepted method of anaerobic capacity assessment stresses anaerobic energy pathways. Based on the utilization of energy production pathways at the point of VO2max and maximal anaerobic capacity attainment a relationship between VO2max and Wingate exercise test protocols may exist. This potential relationship may facilitate the prediction of cardiorespiratory fitness from maximal anaerobic capacity assessed by an incremental treadmill VO2max test and Wingate cycle test respectively. The purpose of this study is to develop prediction equations (gender-independent, gender specific) that predict maximal aerobic capacity using anaerobic power measurements (peak power, mean power, fatigue index) obtained during a 30 second Wingate cycle test as the primary predictor variables along with demographics (sex, age), anthropometrics (height, weight, body fat, seven site skinfolds, thigh girth, hip girth) and resting heart rate as secondary predictor variables. Participants (N=72) completed an incremental treadmill VO2max protocol followed by a Wingate cycle test separated by a 15-20 minute rest period. Eight participants failed to satisfy true VO2max attainment criteria, therefore 64 participants were included in statistical analysis (men n=32; women n=32). Multiple linear regression analysis was used to develop gender-independent and gender specific cardiorespiratory fitness prediction models. Standard error of estimate (SEE) and percent of standard error of estimate (SEE%) were used to assess model accuracy. Predicted residual sum of squares (PRESS) statistics were used to assess model stability. Significance was accepted at the p≤0.05 level. For the gender-independent prediction model sex, height, weight, triceps skinfold, thigh skinfold, body fat, thigh girth, hip girth, resting heart rate (RHR), peak power (PP), mean power (MP), and fatigue index (FI) were significantly correlated to VO2max (r= -0.79, p\u3c0.001; r=0.74, p\u3c0.001; r=0.74, p\u3c0.001; r= -0.53, p=\u3c0.001; r= -0.56, p\u3c0.001; r= -0.60, p\u3c0.001; r=0.42, p=0.001; r=0.35, p=0.005; r= -0.28; p=0.023; r=0.78, p\u3c0.001; r=0.77, p\u3c0.001; r=0.36, p=0.004) respectively. However, peak power (PP), weight, body fat, and RHR were the only significant contributors to the model (p\u3c0.05) producing the following prediction model: Ŷ = 2.627 + (0.001×PP) + (0.037×weight) + (-5.315×body fat) + (-0.019×RHR). This model was determined to be accurate (SEE= 0.37; SEE%=10.89) and stable (R2 = 0.841 vs. R2PRESS = 0.782; SEE = 0.37 vs. SEEPRESS = 0.41). For the male specific model height, weight, thigh girth, PP, MP, and FI were significantly correlated to VO2max (r=0.39, p=0.029; r=0.36, p=0.04; r=0.41, p=0.021; r=0.62, p\u3c0.001; r=0.61, p\u3c0.001; r=0.36, p=0.045) respectively. PP was the only significant contributor to the model revealing the following model: Ŷ = 2758 + (0.002×PP). This model is slightly less accurate than the gender-independent model (SEE=0.49; SEE%=11.98) but not stable (R2 = 0.380 vs. R2PRESS = -0.041; SEE = 0.49 vs. SEEPRESS = 0.61). For the female specific model height, weight, thigh girth, RHR, and MP were significantly correlated to VO2max (r=0.57, p=0.001; r=0.60, p\u3c0.001; r=0.49, p=0.004; r= -0.48, p=0.006; r=0.37; p=0.029) respectively. To maintain an anaerobic power measurement, MP was the only predictor maintained in the model producing a simple linear regression model (Ŷ = 2.061 + 0.002×MP). This model is the least accurate (SEE=0.45; SEE%=16.78) and unstable (R2 = 0.149 vs. R2PRESS = 0.018; SEE = 0.45 vs. SEEPRESS = 0.50). The results of this study indicate the gender-independent model can be generalized to an independent sample of highly active college aged adults. The gender specific models predict VO2max to a similar degree of accuracy to the gender-independent model however, these models are not stable. Therefore, the application of the gender specific models to independent samples of highly active college aged men and women is cautioned

Dissolution and Mechanical properties of Bioresorbable Glass Fibres for use in Paediatric tracheal stents

Stents provide biological support in body conduits and are useful for counteracting stenosis (constriction) in cardiovascular, gastrointestinal, uretheral and airway passages1. However, the current widespread use of permanent metal stents that remain throughout the lifespan of a patient, threaten restenosis, thrombosis, or physical irritation if not surgically removed. In infants the clinical requirement is for a stent that retains structural integrity for periods of several weeks up to many months in vivo during host tissue restoration2 and from a materials perspective this requires an implant with appropriate mechanical and degradation characteristics. Bioresorbable phosphate glass fibres have shown enormous potential for temporary implants and tissue repair, owing to their mechanical properties and solubility in aqueous media which can be modified by addition of various oxide compounds3,4. Further, when combined with degradable polymers the resulting glass fibre polymer composites (GFRP) become ductile allowing them to be forged into supporting scaffolds with suitable mechanical and dissolution properties. To date however, their use for stenting applications has not been investigated possibly due to major difficulties of processing these compositions into fibre form. In this study, two phosphate glass fibre compositions containing SiO2 (silica) and B2O3 (Boron) were fabricated to test the hypothesis that B2O3 containing phosphate glass fibres present enhanced mechanical and dissolution behaviour for use as a degradable stent

Bioactive composites for bone tissue engineering

One of the major challenges of bone tissue engineering is the production of a suitable scaffold material. In this review the current composite materials options available are considered covering both the methods of both production and assessing the scaffolds. A range of production routes have been investigated ranging from the use of porogens to produce the porosity through to controlled deposition methods. The testing regimes have included mechanical testing of the materials produced through to in vivo testing of the scaffolds. While the ideal scaffold material has not yet been produced, progress is being made

Collaboration Between CFIT and the College of Engineering and Design

In the Chef-Driven Contemporary Casual Concepts lab, culinary students were divided into teams to create a restaurant concept. This team of four chose developed The Hottenany, a concept and menu that best represented Lincoln, Nebraska. Students met weekly and to outline the project and delegate tasks. After developing the concept for their menu and logos, the team collaborated with graphic design students. Working as an interdisciplinary team resulted in a richer experience. It provided the opportunity for culinary students to see how their vision was interpreted in design, reinforcing the need for focus and clarity on the concept. It also necessitated a willingness to see the concept from another person’s perspective, which helped refine the concept and menu. This project allowed students to experience real-world situations and learn the importance of communication, meeting deadlines, and planning ahead. For this team, it taught the true meaning and importance of collaboration

Integrating Value for Money and Impact Evaluations: Issues, Institutions, and Opportunities

This mixed methods study investigates why fewer than one in five impact evaluations integrates a value-for-money analysis of the development intervention being evaluated. This study distills four main insights from combined analysis of 33 semi-structured and unstructured interviews, surveys of 497 policy makers and 16 journal editors, and portfolio analyses of World Bank and worldwide impact evaluations. The study finds that low levels of training in cost data collection and analysis methods, together with a lack of standardization of the value-for-money assumptions (e.g., time horizons, discount rates, and economic or financial cost accounting) limit value-for-money integration into impact evaluations. Further eroding researchers' incentives, demand for cost evidence from the journals that publish impact evaluations is mixed. Ill-defined standards of rigor undermine editors' capacity to evaluate the quality of value-for-money analysis when it is integrated with impact evaluation evidence. Institutional funders of impact evaluations do not consistently demand that cost analysis be integrated into their funded evaluations. This study finds no evidence in support of the myth that policymakers do not demand cost evidence. Rather, it finds that researchers have few ways of knowing what kind of analysis policymakers need and when they need it. Improving the stock of impact evaluators who are cross trained in value-for-money methods, establishing standards in what constitutes rigor in costing, resolving methodological issues, and improving linkages between policymakers and researchers would lead to greater integration of value-for-money methods in impact evaluations