Nano-samples give higher brittle strength by the Griffith energy principle.

The purpose of this paper is to show that brittle test samples give a huge size effect that can take several different forms depending on the sample geometry, crack position and mode of force application. Sometimes crack equilibrium force depends on sample dimension or and sometimes the force is independent of area, for example in peel or lap joint cracking. This big size effect arises from the potential energy term in the conservation theory, not considered by Griffith but dominating certain cracks.

New theory explaining Griffith strength results on nano-cracked glass fibres.

The purpose of this paper is to propose a mechanism and theory that can explain the extraordinary increase in measured strength that Griffith observed for glass fibres containing nano-cracks. His 1921 theory (Griffith 1921 221, 163-198. (doi:10.

Energizing ASTM lap joint fracture standards.

Several ASTM standards on the fracture of glued and welded joints need attention because they do not consider the Griffith energy criterion of cracking which was proposed a century ago. It is almost as if Griffith never existed because the ASTM definition of failure is the stress criterion postulated by Galileo in 1638 in which stress at failure (i.e.

Calculations on compact disc cracking.

The Griffith equation for brittle cracking has three problems. First, it applies to an infinite sheet whereas a laboratory test sample is typically near 100 × 100 mm. Second, it describes a central crack instead of the more dangerous and easily observable edge crack.

Complete Genome Sequence of subsp. ATCC 35925.

Here, we report the complete genome sequence of ATCC 35925, an avian isolate from Sweden. The genome gives insight into the ATCC 35925 strain's remarkable ability to tolerate copper and its permissiveness to plasmid transformation.

Calculation of normal contact forces between silica nanospheres.

In this work, interaction forces between two silica nanospheres after contact, including the van der Waals (vdW) attraction, Born repulsion, and mechanical contact forces are studied by molecular dynamics (MD) simulations. The effects of interaction path (approach or departure), initial relative velocity, and relative orientations of two nanospheres are first examined. The results show that the interparticle forces are, to a large degree, independent of these variables.

Red blood cell transfusion: experience in a rural aeromedical transport service.

Introduction: The administration of blood products to critically ill patients can be life-saving, but is not without risk. During helicopter transport, confined work space, communication challenges, distractions of multi-tasking, and patient clinical challenges increase the potential for error. This paper describes the in-flight red blood cell transfusion practice of a rural aeromedical transport service (AMTS) with respect to whether (1) transfusion following an established protocol can be safely and effectively performed, and (2) patients who receive transfusions demonstrate evidence of improvement in condition.

Surfactant protein D (SP-D) alters cellular uptake of particles and nanoparticles.

Surfactant protein D (SP-D) is primarily expressed in the lungs and modulates pro- and anti-inflammatory processes to toxic challenge, maintaining lung homeostasis. We investigated the interaction between NPs and SP-D and subsequent uptake by cells involved in lung immunity. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) measured NP aggregation, particle size and charge in native human SP-D (NhSP-D) and recombinant fragment SP-D (rfhSP-D).

Adhesion of alumina surfaces through confined water layers containing various molecules.

When two surfaces confine water layers between them at the nanoscale, the behavior of these confined water molecules can deviate significantly from the behavior of bulk water, and it could reflect on the adhesion of such surfaces. Thus, the aim of this study is to assess the role of confined water layers on the adhesion of hydrophilic surfaces and how sensitive this adhesion is to the presence of contaminants. Our methodology used under water AFM force measurements with an alumina-sputtered sphere-tipped cantilever and a flat alumina single crystal and then added fractions of ethanol, dimethylformamide, formamide, trimethylamine, and trehalose to water as contaminants.

Particle and nanoparticle interactions with fibrinogen: the importance of aggregation in nanotoxicology.

Ingested, inhaled or injected particles come into contact with biological fluids containing polymers, such as the protein fibrinogen. We studied interactions between well-characterized submicron particles or nanoparticles (NPs) and human fibrinogen. In vitro aggregation and zeta potential measurements of different sized and functionalized polystyrene, carbon black and silica NPs suspended in fibrinogen solutions were made.

A new measure of molecular attractions between nanoparticles near kT adhesion energy.

The weak molecular attractions of nanoparticles are important because they drive self-assembly mechanisms, allow processing in dispersions e.g. of pigments, catalysts or device structures, influence disease through the attraction of viruses to cells and also cause potential toxic effects through nanoparticle interference with biomolecules and organs.

Cold Hearts: a case study of therapeutic hypothermia in helicopter emergency medical services (HEMS).

A 36-year-old white man hit a home run in the seventh inning of a community baseball game. The patient ran the bases successfully and returned to home plate. As he was bending over to pick up the bat, he suddenly collapsed.

Performance of endotracheal intubation and rescue techniques by emergency services personnel in an air medical service.

Background: Literature spanning the last two decades has identified potential harm associated with out-of-hospital endotracheal intubation performed by ground paramedics. Previous researchers have reported intubation success rates of 66% to 97% in the air medical setting.

Objective: To examine the success of endotracheal intubation and rescue techniques performed by air medical personnel during the first eight years of operation of the air ambulance service.

Aggregation and surface properties of iron oxide nanoparticles: influence of pH and natural organic matter.

The interactions between unpurified manufactured nanoparticles (NPs; iron oxide NPs, approximately 7 nm) and standard Suwannee River humic acid (SRHA) were investigated under a range of environmentally relevant conditions. At low pH, approximately 35% of the total iron was in the dissolved phase (< 1 kDa), present from the initial synthesis, whereas at pH more than 4, this concentration was negligible because of the formation of new particles via hydrolysis. Dynamic light scattering results indicated that extensive aggregation of NPs began at approximately pH 5 to 6 and reached a maximum at approximately pH 8.

Developing the reaction kinetics for a biodiesel reactor.

The aim of this paper was to investigate the kinetics of the biodiesel reaction in order to find out how best to reach 96.5% methyl ester. The purity of the biodiesel product was examined using gas chromatography to the EN14214 FAME standard and real-time optical microscopy was used to observe the reaction.

Steam reforming of biodiesel by-product to make renewable hydrogen.

The aim of this paper was to investigate the viability of steam reforming the combined glycerol and water by-product streams of a biodiesel plant. A platinum alumina catalyst was used to optimise the operating conditions for glycerol steam reforming and mass spectroscopy was chosen to measure reformer gas yield. The problem is that glycerol steam reforming is relatively untested even with pure glycerol and the by-product quality may be too poor.

Atomistic studies of surface adhesions using molecular-dynamics simulations.

The existing theoretical descriptions of continuum surface adhesions, such as the JKR (Johnson-Kendall-Roberts) model, have been very useful for the interpretation of particle contacts of sizes down to micrometre length-scales. However, the continuum model is expected to fail at atomic length-scales, where discrete atomistic interactions become significant. The crossover length-scales at which the macroscopic phenomena begin to manifest themselves, and how they occur, are equally baffling and remain poorly understood.

The zoonotic potential of rotavirus.

Rotaviruses are generally species-specific, but cross-species transmission is possible, as has been demonstrated experimentally. Several case studies have indicated infection of humans by animal rotaviruses. Comparison of genetic sequences of human and animal rotaviruses often reveals close identity.