Healing times for circular wounds on plane and spherical bone surfaces

AbstractA mathematical model is developed for the rate of healing of a circular wound in a spherical “skull”. The motivation for this model is based on experimental studies of the “critical size defect” (CSD) in animal models; this has been defined as the smallest intraosseous wound that does not heal by bone formation during the lifetime of the animal [1]. For practical purposes, this timescale can usually be taken as one year. In [2], the definition was further extended to a defect which has less than ten percent bony regeneration during the lifetime of the animal. CSDs can “heal” by fibrous connective tissue formation, but since this is not bone, it does not have the properties (strength, etc.) that a completely healed defect would. Earlier models of bone wound healing [3,4] have focused on the existence (or not) of a CSD based on a steady-state analysis, so the time development of the wound was not addressed. In this paper, the time development of a circular cylindrical wound is discussed from a general point of view. An integro-differential equation is derived for the radial contraction rate of the wound in terms of the wound radius and parameters related to the postulated healing mechanisms. This equation includes the effect of the curvature of the (spherical) skull, since it is clear from the experimental evidence that the size of the CSD increases monotonically with the size of the calvaria. Certain special cases for a planar wound are highlighted to illustrate the qualitative features of the model, in particular, the dependence of the wound healing time on the initial wound size and the thickness of the healing rim

Limiting spheroid size as a function of growth factor source location

AbstractSolutions C(r) of the time-independent nonhomogeneous diffusion equation for three different piecewise-uniform source terms are used to examine the limiting size of multicell spheroids using a simple model which reproduces concentration-dependent mitotic behavior. A condition is derived under which nontrivial solutions do not exist (in all three cases), and a condition for the existence of a unique nontrivial solution is established for the case of growth-modifying factor (GMF) production throughout the spheroid. Qualitative behavior of the limiting size is established as a function of various physiological parameters. Of fundamental importance is the assumed GMF concentration threshold θ, near which (i.e., as C → θ−) mitosis, and hence spheroid growth, is generally strongly inhibited

Prevalence and comorbidities of childhood overweight and obesity among school aged children in an urban settlement in Benin City, Nigeria

Background: The prevalence of childhood overweight and obesity is rising worldwide and its impact spanning through adolescence to adulthood.Objectives: This study aimed to determine the prevalence of overweight and obesity and the occurrence of high blood pressure and elevated blood glucose among school aged children in an urban settlement in Benin City, Nigeria.Design: A cross-sectional, descriptive study was utilized.Subjects and setting: A total of 195 school aged children residing in households in the selected ward were recruited for the study carried out between 2014 and 2015.Outcome measures: Anthropometric measurements were recorded and used to determine the body mass indices (BMI) of the children. Also blood pressure measurements and random blood sugars of the respondents were determined to ascertain the blood pressure and glycaemic status of the children.Results: The proportion of overweight respondents was 7.7% and 3.1% for obesity giving a combined proportion of 10.8% while that for underweight was 11.8% amongst the study respondents. The females, 18 (16.6%) had a significantly higher proportion of overweight and obesity than the males, 3 (3.5%) [p = 0.003]. The prevalence of hypertension was 6 (3.1%) and elevated blood glucose was 4 (2.1%).Conclusion: The prevalence of overweight was 7.7% while that for obesity was 3.1%. Also, the prevalence of hypertension and elevated blood glucose was 3.1% and 2.1% respectively amongst the school aged children and females had a significantly higher proportion of overweight and obesity than males in the study. There is a need for public enlightenment towards promoting healthier lifestyle choices and screening of disease conditions early in childhood.Keywords: Prevalence, Comorbidities, Overweight and obesity, School aged children, Nutritional statu

Marketing Merit Aid: The Response of Flagship Campuses to State Merit Aid Programs

This article identifies the conundrum that exists between removing financial access barriers to college and the student recipients’ inability to sustain reenrollment. After reviewing the findings of 7 research studies related to the impact of financial aid on persistence, the article concludes with a discussion of possible intervention strategies to employ in conjunction with financial aid packages

On the one-loop Kahler potential in five-dimensional brane-world supergravity

We present an on-shell formulation of 5d gauged supergravity coupled to chiral matter multiplets localized at the orbifold fixed points. The brane action is constructed via the Noether method. In such set-up we compute one-loop corrections to the Kahler potential of the effective 4d supergravity and compare the result with previous computations based on the off-shell formalism. The results agree at lowest order in brane sources, however at higher order there are differences. We explain this discrepancy by an ambiguity in resolving singularities associated with the presence of infinitely thin branes.Comment: 20 page

Human Capital Development and Economic Growth in Nigeria

This paper examines the impact of human capital development on economic growth in Nigeria. Theoretical growth models and macroeconomic evidence suggest that human capital accumulation is an important determinant of per capita income growth. However, Hideki et al. (2005) note that outliers, measurement errors, and incorrect specifications may have affected early macroeconomic studies that found a weak relationship between growth and human capital accumulation. While recent studies addressing these problems are beginning to show larger positive effects, the potential endogeneity of human capital accumulation has received relatively little attention. We therefore investigate the relationship between human capital and economic growth in Nigeria with time series data which covers periods 1981-2010. Adopting the endogenous modeling approach cast within the autoregressive distributed lag (ARDL) framework, the bounds testing analysis indicated existence of co integration between economic growth and human capital development indicators. Findings also show that human capital development indicators had positive impact on economic growth in Nigeria within the reviewed periods; however, their impacts were largely statistically insignificant. Further evidence indicated that equilibrium is fully restored for any distortion in the short-run. On this basis of the emanating findings, this study proffered the need for government to invest more in human capital development process and endeavours prioritize the health and education sectors budgeting considering their growth driving potentials in Nigeria. Similarly, government should endeavour to pay attention to the issue of school enrolment. Keywords: Bounds Test, Economic Growth, Endogeneity, Human Capital Development,  Nigeri

Glenoid Dysplasia: Radiographic, Direct MR Arthrographic and Arthroscopic Appearances

AbstractGlenoid dysplasia is an uncommon developmental abnormality of the scapula that is frequently overlooked. We report a case of severe glenoid dysplasia in a 55 year old man and demonstrate its radiographic, direct MR arthrographic and arthroscopic appearances