Mechanical Properties and Biological Responses of Bioactive Glass Ceramics Processed using Indirect SLS

This paper will report on research which aims to generate bone replacement components by processing bioactive glass-ceramic powders using indirect selective laser sintering. The indirect SLS route has been chosen as it offers the ability to tailor the shape of the implant to the implantation site, and two bioactive glass ceramic materials have been processed through this route: apatite-mullite and apatite-wollostanite. The results of bend tests, to investigate mechanical properties, and in vitro and in vivo experiments to investigate biological responses of the materials will be reported, and the suitability of completed components for implant will be assessed.Mechanical Engineerin

SEASAT: A satellite scatterometer illumination times of selected in situ sites

A list of times that the SEASAT A Satellite Scatterometer (SASS) illuminated from directly above or directly abeam, selected surface sites where in situ winds were measured is provided. The list is ordered by the Greenwich Mean Time (GMT) of the midpoint of the illumination period (hit time) for a given surface site. The site identification, the orbit number and the direction from the subtrack in which the truth lies are provided. The accuracy of these times depends in part upon the ascending node times, which are estimated to be within +.1 sec, and on the illumination time relative to the ascending node, which is estimated to be within +6 seconds. The uncertainties in the times provided were judged to be sufficiently small to allow efficient and accurate extraction of SASS and in situ data at the selected surface sites. The list contains approximately six thousand hit times from 61 geographically dispersed sites

Laser sintering of nano-hydroxyapatite coated polyamide 12 powders

As part of a larger study on the laser sintering (LS) of nano-composite structures for biomedical applications, a wet mixing method was used to coat Polyamide 12 (PA12) particles with nano-hydroxyapatite (nHA). The addition of nHA significantly affected powder processability due to laser absorption and heat transfer effects which led to part warping. This phenomenon has not been reported in other studies investigating LS of polymer/HA and nHA powders. Nano-composites containing 0.5–1.5 wt% nHA were successfully produced and tensile testing showed that 0.5 wt% nHA provided the greatest reinforcement with a 20% and 15% increase in modulus and strength respectively. However, the elongation at break had significantly declined which was likely due to the formation of nHA aggregates at the sintering borders following the processing of the coated powders despite being initially well dispersed on the particle surface

Air temperature trends in California

"Greenhouse heating" of the atmosphere due to trace gases seems apparent to those who model with averages but not to those who examine individual temperature records. Temperature trends are on the minds of all those concerned with the environmental influence of the increasing human population. The big problem remains - where and how do we take the Earth's temperature? ... In California, there are 112 temperature records for 1910 to 1989; all of them were used here to examine trends in annual temperature

Fatigue in patients with COPD participating in a pulmonary rehabilitation program

Cindy J Wong1, Donna Goodridge1, Darcy D Marciniuk2, Donna Rennie1,31College of Nursing, 2College of Medicine, 3Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Saskatoon, CanadaBackground: Fatigue is a distressing, complex, multidimensional sensation common in individuals with chronic obstructive pulmonary disease (COPD). While fatigue negatively impacts functional performance and quality of life, there has been little study of the fatigue that affects participants in pulmonary rehabilitation programs. The purpose of this study was to examine the emotional, behavioral, cognitive, and physical dimensions of fatigue and their relationships to dyspnea, mental health, sleep, and physiologic factors.Patients and methods: A convenience sample of 42 pulmonary rehabilitation participants with COPD completed self-report questionnaires which measured dimensions of fatigue using the Multidimensional Fatigue Inventory, anxiety and depression using the Hospital Anxiety and Depression Scale, and sleep quality using the Pittsburgh Sleep Quality Index. Data on other clinical variables were abstracted from pulmonary rehabilitation program health records.Results: Almost all (95.3%) participants experienced high levels of physical fatigue. High levels of fatigue were also reported for the dimensions of reduced activity (88.1%), reduced motivation (83.3%), mental fatigue (69.9%), and general fatigue (54.5%). Close to half (42.9%) of participants reported symptoms of anxiety, while almost one quarter (21.4%) reported depressive symptoms. Age was related to the fatigue dimensions of reduced activity (ρ = 0.43, P < 0.01) and reduced motivation (ρ = 0.31, P < 0.05). Anxiety was related to reduced motivation (ρ = -0.47, P < 0.01). Fatigue was not associated with symptoms of depression, sleep quality, gender, supplemental oxygen use, smoking status, or Medical Research Council dyspnea scores.Conclusions: Fatigue (particularly the physical and reduced motivation dimensions of fatigue) was experienced by almost all participants with COPD attending this pulmonary rehabilitation program. Fatigue affected greater proportions of participants than either anxiety or depression. The high prevalence of fatigue may impact on enrolment, participation, and attrition in pulmonary rehabilitation programs. Further investigation of the nature, correlates, and impact of fatigue in this population is required.Keywords: COPD, fatigue, pulmonary rehabilitation, anxiety, depression, sleep qualit

Activation of the innate immune receptor Dectin-1 upon formation of a 'phagocytic synapse'.

Innate immune cells must be able to distinguish between direct binding to microbes and detection of components shed from the surface of microbes located at a distance. Dectin-1 (also known as CLEC7A) is a pattern-recognition receptor expressed by myeloid phagocytes (macrophages, dendritic cells and neutrophils) that detects β-glucans in fungal cell walls and triggers direct cellular antimicrobial activity, including phagocytosis and production of reactive oxygen species (ROS). In contrast to inflammatory responses stimulated upon detection of soluble ligands by other pattern-recognition receptors, such as Toll-like receptors (TLRs), these responses are only useful when a cell comes into direct contact with a microbe and must not be spuriously activated by soluble stimuli. In this study we show that, despite its ability to bind both soluble and particulate β-glucan polymers, Dectin-1 signalling is only activated by particulate β-glucans, which cluster the receptor in synapse-like structures from which regulatory tyrosine phosphatases CD45 and CD148 (also known as PTPRC and PTPRJ, respectively) are excluded (Supplementary Fig. 1). The 'phagocytic synapse' now provides a model mechanism by which innate immune receptors can distinguish direct microbial contact from detection of microbes at a distance, thereby initiating direct cellular antimicrobial responses only when they are required

Water quality effects of intermittent water supply in Arraiján, Panama

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring.Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause waterquality to degrade in the distribution system.In this study,we characterized waterquality in one study zone with continuous supply and three zoneswith intermittentsupply in the drinking waterdistribution network in Arraija!n,Panama.Low orzero pressuresoccurred in allzones,and negative pressuresoccurred in the continuouszone and two ofthe intermittentzones.Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samplescollected atrandom timeswere positive fortotalcoliform bacteria and only one waspositive for E.coli.Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had !0.2 mg/L free chlorine residual.In contrast,water quality was often degraded during the first-flush period (when supply first returned after an outage).Still, routine and first-flush water quality under intermittent supply was much better in Arraija!n than that reported in a previous study conducted in India.Better waterquality in Arraija!n could be due to betterwaterquality leaving the treatmentplant,shortersupply outages,highersupply pressures,a more consistentand higherchlorine residual,and fewercontaminant sourcesnearpipes.The resultsillustrate thatintermittentsupply and itseffectson waterquality can vary greatly between and within distribution networks.The study also demonstrated thatmonitoring techniques designed specifically for intermittentsupply,such as continuous pressure monitoring and sampling the firstflush,can detectwaterquality threats and degradation thatwould notlikely be detected with conventionalmonitoring

Processing of the ultra-light syntactic foam material Eccostock® FFP using selective laser sintering

Production of custom shaped, low density parts and components has a wide number of industrial applications, but also due to the nature of the material can be challenging [1]. Additive manufacturing forms final parts in a layer by layer process from a stack of 2D sections or slices and allows fabrication of almost any arbitrary 3D shape. Depending on the material and desired pore size, this technique can be used to prepare syntactic foams from open cellular structures as well as from composite materials with a high content of glass microspheres. Eccostock FFP is an off the shelf, epoxy-based composite free-flowing powder. Exposed to the temperatures about 100- 150 °C it cures into the rigid and ultra-light three phase syntactic foam (~ 0.1 g/cc). Material is standardly used for physical support and to provide thermal insulation for delicate electrical components in high vibration environments. In its powder form, it allows material to reach inside densely populated electronic packages and its low shrinkage means that electronic components will not be damaged during the curing procedure. The same characteristics also open the possibility to process this powder using the SLS system and benefit from the design freedom of the additive manufacturing technologies. Selective laser sintering (SLS) is one of the powder bed fusion processes, where parts are built using a laser beam as a heat source inducing fusion between powder particles. Powder is uniformly spread across the building platform and kept heated at a temperature just below the melting and curing point. Interaction with the laser selectively cures the polymer matrix entrapping glass microspheres, while the rest of the powder is unaffected and serves as a support. After each slice, the building platform lowers down a certain distance and a new powder layer is recoated on the surface [2]. In this work we optimised parameters for the processing of the Eccostock FFP powder in the standard SLS machine (EOS Formiga P100). Optimal process temperature and laser energy were defined. Using different sets of parameters we produced compression samples to evaluate mechanical properties of the final parts as well as the influence of the different printing parameters on the part density. We showed that syntactic foams parts can be produced using a relatively low processing temperature (below 70 °C) with short heating and cooling periods and exhibited good dimensional accuracy and shape freedom, making SLS an interesting technology to produce ultra-low density, custom shaped structures for industrial applications. Please click Additional Files below to see the full abstract

Innovation, knowledge spending and productivity growth in the UK: interim report for NESTA 'Innovation Index’ project

Working Pape

Climate and Fisheries: Costs and Benefits of Change

Many records provide the bases for a clearer understanding of the roles of climate regime shifts and short-term perturbations in ecosystem dynamics, hence fisheries responses. Too few have taken the long view of the role of humans in this "Grand Fugue". As one of many predators, it is imperative that humans begin to understand that our various activities are subject to basic ecological principles, such as the concepts of growth limitations imposed by scarcities and habitat debilitations. Most of human history (evolution, growth, colonizations, displacements, resource scarcity, competition for resources) are direct consequences of normal, natural climate fluctuations, and local, regional and global ecological responses. Early fisheries were subsistence levels, with some situations where fishing communities bartered or traded for goods from adjacent highlands or forest cultures. We have also become extremely vulnerable to any persistent climate changes. Following the Medieval Warm period (~900-1180), the onset of the Little Ice Age (LIA) brought changes in regional productivity, disease, and death that began the global transition from Feudal society to the "pay as you go" economics that now dominate the world's major economies. Over the recent two to three centuries humans have swarmed over the remaining terrain, and spread out onto the seas. Modern history relates the continuous growth, expansion and generalized superposition of industrial fisheries onto older coastal subsistence communities, initiating extensive competition, overexploitation, and with resultant dwindling resources and habitat destruction. I have started a Timeline of Fisheries Development that provides a framework of information upon which these facts are derived: I will continue to develop the Timeline, so that others might learn how humans resolve the issues of complex aquatic ecosystems, limited resource sharing, or not.KEYWORDS: Climate, Fisheries, History, Cultures, Economics, Ecosystems, Environment