Mechanobiology of platelets: techniques to study the role of fluid flow and platelet retraction forces at the micro- and nano-scale

Coagulation involves a complex set of events that are important in maintaining hemostasis. Biochemical interactions are classically known to regulate the hemostatic process, but recent evidence has revealed that mechanical interactions between platelets and their surroundings can also play a substantial role. Investigations into platelet mechanobiology have been challenging however, due to the small dimensions of platelets and their glycoprotein receptors. Platelet researchers have recently turned to microfabricated devices to control these physical, nanometer-scale interactions with a higher degree of precision. These approaches have enabled exciting, new insights into the molecular and biomechanical factors that affect platelets in clot formation. In this review, we highlight the new tools used to understand platelet mechanobiology and the roles of adhesion, shear flow, and retraction forces in clot formation.     

Performance Evaluation of Deteriorating Highway Bridges Located in High Seismic Areas

This paper studies the life-cycle performance and cost of reinforced concrete highway bridges subjected to earthquake ground motions while they are continuously exposed to the attack of chloride ions. The penetration of chloride ions into the concrete is simulated through a finite difference approach that takes into account all the parameters that can affect the corrosion process. From simulation results, the corrosion initiation time is predicted, and the extent of structural degradation is calculated over the entire life of the bridge. A group of detailed bridge models with various structural attributes are developed to evaluate the changes in the structural capacity and seismic response of corroded bridges. For the purpose of the probabilistic seismic risk assessment of bridges, the seismic fragility curves are generated and updated at regular time intervals. The time-dependent fragility parameters are employed to investigate the life-cycle cost of bridges by introducing a performance index that combines the effects of probable seismic events and chloride-induced corrosion. The proposed approach provides a multihazard framework that leads to more realistic performance and cost estimates.     

The Effect of Remote Center Compliance Parameters on Formation Control of Cooperative Wheeled Mobile Robots for Object Manipulation

International Journal of Control, Automation and Systems - Formation control is a potential advanced technology for aircrafts, spacecrafts and space robots. This paper, for the first time, studies...     

Semi-automatic measurement of rigid gas-permeable contact lens movement in keratoconus patients using blinking images

Purpose

To introduce a method for estimation of the rigid gas-permeable contact lens (RGP) movement.

Pro-labour myometrial gene expression: are preterm labour and term labour the same?

Preterm labour (PTL) is the most important cause of neonatal morbidity and mortality. While some causes have been identified, the mechanisms involved remain elusive. This study investigates whether term labour (TL) is an appropriate model for PTL by examining pro-labour gene expression, using quantitative rtPCR, and protein synthesis, using Western analysis, in preterm and term myometrial samples obtained from the upper and lower uterine segments before and after the onset of labour. In the lower segment, the levels of prostaglandin H synthase type-2 (PGHS-2), interleukin-1beta (IL-1beta), IL-6 and IL-8 mRNA expression were significantly higher in TL compared with PTL samples. Compared with non-labour controls, the expression of IL-1beta and IL-8 mRNA was increased in both PTL and TL samples and the expression of PGHS-2 and IL-6 mRNA was increased in TL samples only. In the upper segment, there were no differences between PTL and TL samples and the mRNA expression of PGHS-2 and IL-1beta was increased in TL compared with term no labour samples. No effect of PTL or TL was seen on either oxytocin receptor or connexin-43 mRNA expression or protein levels. The multiple regression analysis and studies in primary cultures of uterine myocytes suggest that the inflammatory cytokines, IL-1beta and tumour necrosis factor-alpha, are the most important regulators of PGHS-2 and IL-8. Our data show that preterm and term labouring myometrium are significantly different and that the most marked labour-induced changes in gene expression are in the lower segment. These changes may occur in response to the release of inflammatory cytokines by the labour-associated inflammatory infiltration.     

Impact of storage time and temperature on thermal inactivation of Salmonella Enteritidis PT 30 on oil-roasted almonds

Whole Nonpareil variety almonds were inoculated with Salmonella Enteritidis PT 30 and stored at 4 or 23 °C for up to 48 wk. At 1, 12, 24, 37, and 48 wk of storage, almonds were heated by immersion in 121 °C oil. After heating for 0.5 to 2.5 min, almonds were drained, transferred to tryptic soy broth, and mixed with a stomacher prior to plating onto tryptic soy and bismuth sulfite agars. Over the 48 wk of storage, Salmonella declined by 0.5 and 2.1 log CFU/g at 4 and 23 °C, respectively. The survivor inactivation curves were upwardly concave with rapid initial reductions in the levels of Salmonella. For up to 24 wk of storage, the mean counts of the survivors after treatment were not significantly different. The Weibull model predicted 4- and 5-log reductions of Salmonella in 0.85 ± 0.16 and 1.8 ± 0.43 min, respectively, for almonds stored at 4 °C, and in 1.6 ± 0.53 and 3.2 ± 1.0 min, respectively, for almonds stored at 23 °C. Refrigerated storage had little impact on heat resistance of Salmonella that were inoculated on almonds. PRACTICAL APPLICATION: This research provides information of value in performing or evaluating validation studies for thermally processed almonds. The sensitivity of Salmonella to oil roasting is demonstrated during typical commercial almond storage times and temperatures.     

Design adaptations in a large and deep urban excavation: Case study

In this paper, design, re-design, and performance of a long-standing very deep excavation, which was originally planned to depth of 38 m, are presented. Over-digging was not planned in the original design, thus the reassessment was performed. Two main topics were followed: deepening to increase the maximum depth of an existent excavation from 38 m to 42.5 m, and feasibility for upgrading a predesigned support system from temporary to permanent support system. The geological investigations in the project site illustrated a type of stiff and cemented coarse-grained alluvium. An observational approach with additional geotechnical investigations and in situ tests was applied. Back analyses of stability of an unsupported access ramp, as well as deformation monitoring of walls, were used in order to review geotechnical design parameters that represent the full-scale behavior of the ground. Additional nails and soldier piles together with building mat foundation were implemented as a complementary lateral support in the retaining system. From an engineering point of view, by assuming a corrosion rate of 0.065 mm/a for existent rebars, according to chemical and electrical resistivity tests, the long-term performance of the revised retaining system was verified by static and pseudo-dynamic ultimate limit state analyses. Performance monitoring during the construction shows that the measured deformation is in the lower limit of the prediction.