Low Numbers of FOXP3 Positive Regulatory T Cells Are Present in all Developmental Stages of Human Atherosclerotic Lesions

BACKGROUND: T cell mediated inflammation contributes to atherogenesis and the onset of acute cardiovascular disease. Effector T cell functions are under a tight control of a specialized T cell subset, regulatory T cells (Treg). At present, nothing is known about the in situ presence of Treg in human atherosclerotic tissue. In the present study we investigated the frequency of naturally occurring Treg cells in all developmental stages of human atherosclerotic lesions including complicated thrombosed plaques. METHODOLOGY: Normal arteries, early lesions (American Heart Association classification types I, II, and III), fibrosclerotic plaques (types Vb and Vc) and 'high risk' plaques (types IV, Va and VI) were obtained at surgery and autopsy. Serial sections were immunostained for markers specific for regulatory T cells (FOXP3 and GITR) and the frequency of these cells was expressed as a percentage of the total numbers of CD3+ T cells. Results were compared with Treg counts in biopsies of normal and inflammatory skin lesions (psoriasis, spongiotic dermatitis and lichen planus). PRINCIPLE FINDINGS: In normal vessel fragments T cells were virtually absent. Treg were present in the intima during all stages of plaque development (0.5-5%). Also in the adventitia of atherosclerotic vessels Treg were encountered, in similar low amounts. High risk lesions contained significantly increased numbers of Treg compared to early lesions (mean: 3.9 and 1.2%, respectively). The frequency of FOXP3+ cells in high risk lesions was also higher compared to stable lesions (1.7%), but this difference was not significant. The mean numbers of intimal FOXP3 positive cells in atherosclerotic lesions (2.4%) was much lower than those in normal (24.3%) or inflammatory skin lesions (28%). CONCLUSION: Low frequencies of Treg in all developmental stages of human plaque formation could explain the smoldering chronic inflammatory process that takes place throughout the longstanding course of atherosclerosis

Using Exotic Materials Like EuD4TEA and MgD4TEA to Monitor Damage and Radiation Exposure in Extreme Environments

Space radiation poses a significant challenge to exploration missions to the Moon, Mars, and beyond. As we consider long duration space missions, the risk from radiation exposure increases. There is no simple technique that is capable of real-time radiation detection. Past research shows that the fluorescence yield and decay time are both functions of temperature and radiation fluence. Each of these parameters need to be investigated separately in order to fully understand the physical properties for any useful phosphor. Once the temperature dependencies are known, then the radiation fluence in the surrounding environment can be estimated. This paper will discuss recent research on europium and magnesium tetrakis dibenzoylmethide triethylammonium (EuD4TEA and MgD4TEA) that could be used to measure radiation and temperature in real time. Both of these organic materials have been shown to be sensitive to proton radiation and to changes in temperature

Introduction to triboluminescence

Triboluminescence phenomenon has generated extensive research interest over the years since it was reportedly discovered in the sixteenth century by Sir Francis Bacon. Triboluminescent materials are being developed into damage, stress, and impact sensors in diverse engineering systems such as civil and aerospace structures. This introductory chapter provides an overview of the place of triboluminescence within the luminescence spectrum. It also describes the three forms of triboluminescence identified in literature mainly elastico, plastico, and fracto triboluminescence. Results of studies in identifying most promising triboluminescent materials for sensors are also reported

Mechanical, spectral, and luminescence properties of ZnS:Mn doped PDMS

Zinc sulfide doped with manganese (ZnS:Mn) is one of the brightest triboluminescent materials known and has been studied for a variety of applications. The powder form of this material restricts its safe handling and utilization, which limits the range of applications that can take advantage of its unique properties. In this study, the tribo- and photo-luminescent properties as well as the mechanical properties of ZnS:Mn encapsulated in an inert and optically transparent elastomer - Sylgard 184, have been investigated and fully characterized. ZnS:Mn particles of 8.5 μm diameter were incorporated into the Sylgard 184 polymer matrix prior to the curing stage with increasing amounts targeting a final (mass) concentration of 5%, 15%, and 50%. Additionally, the effect of the ZnS:Mn particles on the overall surface properties of the encapsulating elastomer was investigated and reported here. It was observed that the triboluminescent emission from impact scales with phosphor concentration and was not affected by the encapsulating medium

Enhanced physicochemical properties of polydimethylsiloxane based microfluidic devices and thin films by incorporating synthetic micro-diamond

Synthetic micro-diamond-polydimethylsiloxane (PDMS) composite microfluidic chips and thin films were produced using indirect 3D printing and spin coating fabrication techniques. Microfluidic chips containing up to 60 wt% micro-diamond were successfully cast and bonded. Physicochemical properties, including the dispersion pattern, hydrophobicity, chemical structure, elasticity and thermal characteristics of both chip and films were investigated. Scanning electron microscopy indicated that the micro-diamond particles were embedded and interconnected within the bulk material of the cast microfluidic chip, whereas in the case of thin films their increased presence at the polymer surface resulted in a reduced hydrophobicity of the composite. The elastic modulus increased from 1.28 for a PDMS control, to 4.42 MPa for the 60 wt% composite, along with a three-fold increase in thermal conductivity, from 0.15 to 0.45 W m−1 K−1. Within the fluidic chips, micro-diamond incorporation enhanced heat dissipation by efficient transfer of heat from within the channels to the surrounding substrate. At a flow rate of 1000 μL/min, the gradient achieved for the 60 wt% composite chip equalled a 9.8 °C drop across a 3 cm long channel, more than twice that observed with the PDMS control chip