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The purpose of this project was to explore the feasibility of powering a climate control system solely from a renewable energy source. The off-the-shelf cooling system components were taken from a ca. 1986 R-12 residential refrigerator and then reassembled onto a custom enclosure which was constructed to serve as the climate-controlled compartment. The enclosure design was purposefully simple: a rectangular shaped box constructed out of plywood and mounted on wheels together with a plexiglass door which was substituted for the front face. The overall design provided for enhanced mobility while also allowing for easy observation of the interior temperature via an interior-mounted, digital, commercial residential thermostat integrated into the control system. The system, nominally, is triggered by incident solar radiation; the initial set-point temperature was 21 °C. Compressor power was derived solely from renewable energy. Specifically, a pair of 100W 12V monocrystalline silicon photovoltaic solar panels was used to generate electricity which was subsequently stored in a deep-cycle battery. Under steady-state AC operation, the compressor draws approximately 2.1A. Due to system inefficiencies, the corresponding DC current draw is necessarily higher and approaches 22.3A. For a compressor duty cycle ranging from 50–100%, the current draw over a model 9 hr day would range from between 100.1–200.3 A-H. The lower limit is within the energy storage capacity for the fully-charged system, as currently designed.

This Full Paper in the Research category examines the use of self-regulated learning in a service-learning project carried out as part of our First-Year Seminar in Engineering coursework. The service-learning project in this course requires that, under a specific project theme given, students complete an engineering project from inception and detailed design to implementation to meet identified community needs. A successful completion of the service-learning project is attributed to key aspects of self-regulated learning. Evaluated with a subset of the Engineering Design Metacognitive Questionnaire, our study shows that first-year engineering students’ use of SRL is at a reasonable level and, compared to the results reported in the literature, not less than the use of SRL by engineering seniors assessed in two pilot studies with capstone design projects.

Innate immunity depends on the coordinated activity of multiple leukocytes at or near the site of tissue injury. Previous numerical studies have shown that an adherent leukocyte can hydrodynamically recruit a free-stream leukocyte towards the endothelial surface. Using a computer model we created, we numerically investigated the hydrodynamic recruitment of circulating cells due to the presence of a nearby adherent deformed cell. For circulating cells positioned one diameter or more above the reactive surface and subsequently involved in a glancing (out-of-plane) collision with an adherent cell, the simulation indicated that the free-stream cell could be driven closer to the surface. This behavior was seen to depend, in part, on the offset glancing distance. Furthermore, for a deformed adherent cell a similar effect was observed, but beginning at smaller offset glancing distances. We also examined the binary interaction for a free-stream cell initially less than one diameter above the surface. For fixed offset glancing distances, the binary interaction with a more significantly deformed adherent cell resulted in enhanced recruiting effectiveness, as quantified by the time needed for the cell to descend to a height where receptor-ligand interactions were possible.

Background and Aims Past research has examined eating disorder risk among college students majoring in Nutrition and has suggested an increased risk, while other studies contradict these results. Exercise Science majors, however, have yet to be fully examined regarding their risk for eating disorders and exercise dependence. Based on pressures to fit the image associated with careers related to these two disciplines, research is warranted to examine the potential risk for both eating disorder and exercise dependence. The purpose of this study is to compare eating disorder risk, exercise dependence, and body weight dissatisfaction (BWD) between Nutrition and Exercise Science majors, compared to students outside of these career pathways. Methods Participants (n = 89) were divided into three groups based on major; Nutrition majors (NUTR; n = 31), Exercise Science majors (EXSC; n = 30), and other majors (CON; n = 28). Participants were given the EAT-26 questionnaire and the Exercise Dependence Scale. BWD was calculated as the discrepancy between actual BMI and ideal BMI. Results The majority of participants expressed a desire to weigh less (83%) and EXSC had significantly (p = .03) greater BWD than NUTR. However, there were no significant differences in eating disorder risk or exercise dependence among majors. Discussion and Conclusions This study suggested there was no significant difference in eating disorder risk or exercise dependence between the three groups (NUTR, EXSC, and CON).

Innate immunity is characterized by the coordinated activity of multiple leukocytes mobilizing at or near the site of tissue injury. Slow rolling and/or adherent leukocytes have been shown to hydrodynamically recruit free-stream leukocytes to a model of inflamed tissue. In this paper, we numerically investigate the hydrodynamic recruitment of free-stream leukocytes due to the presence of a nearby adherent, deformed leukocyte by using a computational model developed from first principles to simulate these types of interactions. For free-stream cells at least one diameter above the surface and subsequently involved in a glancing (out-of-plane) collision with one or more adherent cell, the simulation indicated that the free-stream cell was driven closer to the surface as a function of increasing glancing distance. Further, with increasing deformation of the adherent cell a similar effect was observed beginning at smaller glancing offsets. The influence of binary interactions on the trajectories of free-stream cells that were less than one diameter above the surface was also examined. For fixed glancing distance, increased adherent cell deformation led to enhanced recruiting effectiveness which was quantified by determining the time needed for the free-stream cell to enter the reactive zone; that is, a membrane separation distance such that receptor-ligand binding was possible. This effectiveness was only moderately influenced by variations in shear rate and cell buoyancy. Finally, for large glancing offset the domain of influence of the adherent cell diminished and the trajectory of the free-stream cell was unaffected by the adherent cell, with regard to hydrodynamic recruitment.

Leukocyte trafficking in the microvasculature during inflammatory response is known to involve multiple adhesion molecules and is referred to as the leukocyte adhesion cascade (LAC). Surface-bound selectins and their respective ligands are primarily responsible for tethering and rolling of leukocytes over inflamed endothelium. Numerical modeling of this response is challenging due to the nature of cell–cell interactions in Stokes flow (i.e., large domain of influence for each cell over its neighbors). Here, we discuss a novel simulation capable of modeling several steps of the LAC. The new model includes relevant contact and lubrication forces and extends a physics-based model for single particle rolling interactions developed by Hammer and Apte (1992) , for multiparticle interactions by King and Hammer (2001a) , and for deformable particles by Gee and King (2006) . We initially demonstrate the model for cell–cell collisions occurring near a planar substrate, and for cell–substrate adhesive interactions. The adhesion studies provide a new perspective of the contribution of Hertzian contact mechanics toward variations in contact area at the cell–substrate interface. The results confirm that interfacial contact area will increase as a result of the contact formulation and that this mechanism may enhance cell rolling interactions for cells driven toward endothelium by cell–cell collisions. As a result of cell compliance, rolling velocity may decrease significantly, compared to non-compliant cells.

Particle suspensions are common to biological fluid flows; for example, flow of red- and white-blood cells, and platelets. In medical technology, current and proposed methods for drug delivery use membrane-bounded liquid capsules for transport via the microcirculation. In this paper, we consider a 3D linear elastic particle inserted into a Newtonian fluid and investigate the time-dependent deformation using a numerical simulation. Specifically, a boundary element technique is used to investigate the motion and deformation of initially spherical or spheroidal particles in bounded linear shear flow. The resulting deformed shapes reveal a steady-state profile that exhibits a 'tank-treading' motion for initially spherical particles. Wall effects on particle trajectory are seen to include a modified Jeffrey׳s orbit for spheroidal inclusions with a period that varies inversely with the strength of the shear flow. Alternately, spheroidal inclusions may exhibit either a 'tumbling' or 'trembling' motion depending on the initial particle aspect ratio and the capillary number (i.e., ratio of fluid shear to elastic restoring force). We find for a capillary number of 0.1, a tumbling mode transitions to a trembling mode at an aspect ratio of 0.87 (approx.), while for a capillary number of 0.2, this transition takes place at a lower aspect ratio. These oscillatory modes are consistent with experimental observations involving similarly shaped vesicles and thus serves to validate the use of a simple elastic constitutive model to perform relevant physiological flow calculations.

A second-derivative scan of an acidified urine sample allows the amplitude of deflection (delta A) and the minimum wavelength of the trough (lambda min) to determine the correct porphyrin concentration and the coproporphyrin:uroporphyrin (copro:uro) ratio, respectively, from a nomogram constructed from calibrator solutions. We measured 24 urine samples for total porphyrin as coproporphyrin equivalents and adjusted the results with factors from the nomogram. The adjusted results (x) (mean +/- SE, 501 +/- 57 nmol/L) compared favorably with the expected results (y) (514 +/- 57). The regression equation and correlation coefficient were: y = 0.993x - 8.9 (r = 0.998, S(y/x) = 16.2). Results of the copro:uro ratio derived by second-derivative spectroscopy and HPLC showed no significant difference (chi 2-test) from samples with various copro:uro ratios. Recovery studies on four urine samples supplemented with known proportions of coproporphyrins and uroporphyrins gave good agreement between the measured and the expected porphyrin ratios. The overall imprecision (CV) of the assay ranged from 3.6% to 6.0% for coproporphyrin and from 3.2% to 9.1% for uroporphyrin.

Human leukaemic HL-60 cells are widely used for studying interactions involving adhesion molecules [e.g. P-selectin and PSGL-1 (P-selectin glycoprotein ligand-1)] since their rolling behaviour has been shown to mimic the dynamics of leucocyte rolling in vitro. HL-60 cells are neutrophilic promyelocytes that can undergo granulocytic differentiation upon exposure to compounds such as DMSO (dimethylsulfoxide). Using a parallel plate flow chamber functionalized with recombinant P-selectin–Fc chimaera, undifferentiated and DMSO-induced (48, 72 and 96 h) HL-60 cells were assayed for rolling behaviour. We found that depending on P-selectin incubation concentration, undifferentiated cells incurred up to a 6-fold increase in rolling velocity while subjected to an approximately 10-fold increase in biologically relevant shear stress. HL-60 cells exposed to DMSO for up to 72 h incurred up to a 3-fold increase in rolling velocity over the same shear stress range. Significantly, cells exposed for up to 96 h incurred up to a 9-fold decrease in rolling velocity, compared with undifferentiated HL-60 cells. Although cell surface and nuclear morphological changes were evident upon exposure to DMSO, flow cytometric analysis revealed that PSGL-1 expression was unchanged, irrespective of treatment duration. The results suggest that DMSO-treated HL-60 cells may be problematic as a substitute for neutrophils for trafficking studies during advanced stages of the LAC (leucocyte adhesion cascade). We suggest that remodelling of the cell surface during differentiation may affect rolling behaviour and that DMSO-treated HL-60 cells would behave differently from the normal leucocytes during inflammatory response in vivo.

CONTRIBUTORS. 1 Introduction (Michael R. King and David J. Gee). PART I: APPLICATIONS IN NANOTECHNOLOGY. 2 Multiscale Modeling of Nanoscale Aggregation Phenomena: Applications in Semiconductor Materials Processing (Talid Sinno). 3 Multiscale Modeling of Rare Events in Self-Assembled Systems (Dmitry I. Kopelevich). 4 Continuum Description of Atomic Sheets (Constantine Pozrikidis). 5 Coulombic Dragging and Mechanical Propelling of Molecules in Nanofluidic Systems (Petr Kral and Boyang Wang). 6 Molecular Dynamics Modeling of Nanodroplets and Nanoparticles (D. Lussier, N.M.P. Kakalis, and Y. T. Ventikos). 7 Modeling the Interactions Between Compliant Microcapsules and Patterned Surfaces (Anna C. Balazs and Alexander Alexeev). PART II: APPLICATIONS IN BIOLOGY. 8 Coarse-Grained and Multiscale Simulations of Lipid Bilayers (Harry A. Stern). 9 Stochastic Approach to Biochemical Kinetics (Ian J. Laurenzi). 10 In Silico Modeling of Angiogenesis at Multiple Scales: From Nanoscale to Organ System (Amina A. Qutub, Feilim Mac Gabhann, Emmanouil D. Karagiannis, and Aleksander S. Popel). 11 Large-Scale Simulation of Blood Flow in Microvessels (Prosenjit Bagchi). 12 Molecular to Multicellular Deformation During Adhesion of Immune Cells Under Flow (David J. Gee and Michael R. King). INDEX.

A modification of the colorimetric method of Bergman and Loxley for the measurement of urinary hydroxyproline using external aqueous hydroxyproline standards instead of individual internal standards is described. We show that this modification leads to an underestimation (average 32%) of hydroxyproline because suppression of colour development occurs in urine samples but not in aqueous standards. Use of an internal standard for each urine test corrects for this suppression. Recovery of hydroxyproline (250 mumol/L) added to 12 patient urine samples averaged 99% and the overall imprecision for the assay was then less than 5%. Modifications to the original hydrolysis and colour development procedures allow linearity to 1500 mumol/L. Details of our procedure are given.