Influence of Human Jaw Periosteal Cells Seeded β-Tricalcium Phosphate Scaffolds on Blood Coagulation

Tissue engineering offers auspicious opportunities in oral and maxillofacial surgery to heal bone defects. For this purpose, the combination of cells with stability-providing scaffolds is required. Jaw periosteal cells (JPCs) are well suited for regenerative therapies, as they are easily accessible and show strong osteogenic potential. In this study, we analyzed the influence of uncoated and polylactic-co-glycolic acid (PLGA)-coated β-tricalcium phosphate (β-TCP) scaffolds on JPC colonization and subsequent osteogenic differentiation. Furthermore, interaction with the human blood was investigated. This study demonstrated that PLGA-coated and uncoated β-TCP scaffolds can be colonized with JPCs and further differentiated into osteogenic cells. On day 15, after cell seeding, JPCs with and without osteogenic differentiation were incubated with fresh human whole blood under dynamic conditions. The activation of coagulation, complement system, inflammation, and blood cells were analyzed using ELISA and scanning electron microscopy (SEM). JPC-seeded scaffolds showed a dense cell layer and osteogenic differentiation capacity on both PLGA-coated and uncoated β-TCP scaffolds. SEM analyses showed no relevant blood cell attachment and ELISA results revealed no significant increase in most of the analyzed cell activation markers (β-thromboglobulin, Sc5B-9, polymorphonuclear (PMN)-elastase). However, a notable increase in thrombin-antithrombin III (TAT) complex levels, as well as fibrin fiber accumulation on JPC-seeded β-TCP scaffolds, was detected compared to the scaffolds without JPCs. Thus, this study demonstrated that besides the scaffold material the cells colonizing the scaffolds can also influence hemostasis, which can influence the regeneration of bone tissue.     

Illustrative stream surfaces

Stream surfaces are an intuitive approach to represent 3D vector fields. In many cases, however, they are challenging objects to visualize and to understand, due to a high degree of self-occlusion. Despite the need for adequate rendering methods, little work has been done so far in this important research area. In this paper, we present an illustrative rendering strategy for stream surfaces. In our approach, we apply various rendering techniques, which are inspired by the traditional flow illustrations drawn by Dallmann and Abraham \& Shaw in the early 1980s. Among these techniques are contour lines and halftoning to show the overall surface shape. Flow direction as well as singularities on the stream surface are depicted by illustrative surface streamlines. ;To go beyond reproducing static text book images, we provide several interaction features, such as movable cuts and slabs allowing an interactive exploration of the flow and insights into subjacent structures, e.g., the inner windings of vortex breakdown bubbles. These methods take only the parameterized stream surface as input, require no further preprocessing, and can be freely combined by the user. We explain the design, GPU-implementation, and combination of the different illustrative rendering and interaction methods and demonstrate the potential of our approach by applying it to stream surfaces from various flow simulations. ;     

Analysis of diverse simulation models for combustion engine journal bearings and the influence of oil condition

The paper deals with the comparison of different models, from simple to complex, for the simulation of non-stationary response of the journal bearings used in combustion engines. The variety of simulation models covers classical methods from Holland, Butenschoen and numerical methods based on the Hydrodynamic (HD), Elasto-hydrodynamic (EHD) and Thermo-elasto-hydrodynamic (TEHD) lubrication theory. Several crankshaft main bearings and connecting rod big end bearings are investigated. The comparison includes the following bearing parameters: Peak Oil Film Pressure (POFP), Minimum Oil Film Thickness (MOFT) and oil flow. Calculation time is compared, too. Estimation of oil viscosity is discussed over a typical temperature and pressure range found in combustion engines, including the influence of the fuel dilution as an example of the oil aging phenomena.     

Post-occupancy evaluation of residents of single- and multi-family earth-sheltered housing

This paper presents the results of a study of user response to an earth-sheltered residential environment, based on interviews and a questionnaire. Data was collected in 1980 from 39 subjects living in 22 single- and multi-family earth-sheltered homes in the Minneapolis-St Paul, Minnesota (U.S.A.) area. The paper discusses results of the study in terms of the socioeconomic characteristics of the respondents and the characteristics of the earth-sheltered homes studied, as well as consumer attitudes toward and level of satisfaction with earth-sheltered living. The study found that current residents of earth-sheltered houses were very satisfied with their homes and that their attitudes toward their residential environment appeared to improved after they had lived in the homes. The paper includes a review of the literature involving studies of consumer attitudes toward earth-sheltered housing.     

A study of the rheological behaviour of multigrade oils

The rheological behaviour of four blends of multigrade oils containing different commercial viscosity index improvers has been studied for increasing shear rate and temperature. Polyalkylmethacrylate has been found to demonstrate different behaviour to styrene-isoprene, styrene-butadiene and ethylene-propylene copolymers. Oil blends for all these hydrocarbon copolymers have shown non-Newtonian behaviour with increasing shear rate (0 to 35,000 s⁻¹) at low and moderate temperatures (−15 to 40°C), i.e. their viscosities were subject to a significant decrease, while the viscosity of the polyalkyl-methacrylate blend showed a limited decrease. With increasing shear rate at high temperature (100°C), all the formulated blends behaved as Newtonian fluids, i.e. with nearly constant viscosities. Increasing shear rate can also change the behaviour of some hydrocarbon copolymers from thickeners to viscosity index improvers.     

Theistic existential psychotherapy.

Recently, the dichotomy between psychotherapy and spirituality has weakened as scholars and practitioners have begun to acknowledge the value of spiritual factors in clients’ lives. This article integrates I. D. Yalom’s (1980) existential psychotherapy with the theistic worldview and with the assumptions and ideas of theistic scholars such as Kierkegaard. The philosophical foundations of Yalom’s existential psychotherapy are contrasted with those of theism. A theistic reconceptualization of existential personality theory is presented, and the existential approach to treatment is reconsidered in light of theism. Finally, a case vignette involving fear of love loss is presented to illustrate how a theistic perspective can enhance the practice of existential psychotherapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)