Pump less wearable microfluidic device for real time pH sweat monitoring

This paper presents the fabrication and the performance of a novel, wearable, robust, flexible and disposable microfluidic device which incorporates micro-Light Emitting Diodes (μ-LEDs) as a detection system, for monitoring in real time mode the pH of the sweat generated during an exercising period

The Kato square root problem on vector bundles with generalised bounded geometry

We consider smooth, complete Riemannian manifolds which are exponentially locally doubling. Under a uniform Ricci curvature bound and a uniform lower bound on injectivity radius, we prove a Kato square root estimate for certain coercive operators over the bundle of finite rank tensors. These results are obtained as a special case of similar estimates on smooth vector bundles satisfying a criterion which we call generalised bounded geometry. We prove this by establishing quadratic estimates for perturbations of Dirac type operators on such bundles under an appropriate set of assumptions.Comment: Slight technical modification of the notion of "GBG constant section" on page 7, and a few technical modifications to Proposition 8.4, 8.6, 8.

Dynamical description of vesicle growth and shape change

We systematize and extend the description of vesicle growth and shape change using linear nonequilibrium thermodynamics. By restricting the study to shape changes from spheres to axisymmetric ellipsoids, we are able to give a consistent formulation which includes the lateral tension of the vesicle membrane. This allows us to generalize and correct a previous calculation. Our present calculations suggest that, for small growing vesicles, a prolate ellipsoidal shape should be favored over oblate ellipsoids, whereas for large growing vesicles oblates should be favored over prolates. The validity of this prediction is examined in the light of the various assumptions made in its derivation.Comment: 6 page

The physicochemical characterisation of pepsin degraded pig gastric mucin

Mucins are the main macromolecular components of the mucus secretions that cover the oral cavity, gastrointestinal and urogenital tracts of animals. The properties of the mucus secretions are therefore directly correlated with the physicochemical properties of mucin glycoproteins. In this study, mucins were obtained from pig gastric mucous after digestion with pepsin at 37 ⁰C for 4 hours, these mucins were characterised in terms of compositional and hydrodynamic properties. Compositional analysis showed that this mucin contains protein (15%), carbohydrates (55%) of which the constituents are: fucose (4%), galactose (9%), glucosamine (55%), glucosamine (33%) and sialic acid (2%). The latter component gives the mucin polymer a pH-dependant negative charge, with a -potential of -3 mV at pH 1.2 up to -11 mV at pH 7.4. The weight average molar mass was ~1 x 106 g/mol and intrinsic viscosity was ~0.42 dL/g although there was a small pH dependency due to the polyelectrolyte behaviour of the polymer. The measurements of viscosity versus shear rate showed shear thinning behaviour and the critical overlap concentration was determined to be 10-11% w/v indicating a compact structure. Knowledge of these properties is fundamental to the understanding interactions of mucins, with for example, novel drug delivery systems

USP compendial methods for analysis of heparin: chromatographic determination of molecular weight distributions for heparin sodium

Heparin is a polysaccharide product isolated from glycosaminoglycans of porcine mucosa (or occasionally other tissues and species). It is a linear non-uniform polymer consisting of alternating glucosamine and uronic acid monosaccharide residues and is highly sulfated. Heparin sodium drug product (HP) used in medicine consists of chains with molecular weight (MW) ranging from under 5,000 to over 50,000. Although HP has been used as an injectable antithrombotic medicine for more than 70 years, many aspects of its structure and purity, including its MW, have not been specified by public standards until recent years. In 2008, a number of HP lots associated with severe adverse effects, including fatalities, were found to have been contaminated with oversulfated chondroitin sulfate. This incident led to thorough revision of compendial standards worldwide. In the USA, the Food and Drug Administration (FDA) encouraged the inclusion of enhanced standards for purity and identity in the relevant monographs of the United States Pharmacopeia (USP) including acceptance criteria for MW distribution

Airports at Risk: The Impact of Information Sources on Security Decisions

Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport employees in European Airports across the continent, we analyzed how both formal and informal sources of security information affect employee's decisions to comply with the security rules and directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels

Adjusting bone mass for differences in projected bone area and other confounding variables: an allometric perspective.

The traditional method of assessing bone mineral density (BMD; given by bone mineral content [BMC] divided by projected bone area [Ap], BMD = BMC/Ap) has come under strong criticism by various authors. Their criticism being that the projected bone "area" (Ap) will systematically underestimate the skeletal bone "volume" of taller subjects. To reduce the confounding effects of bone size, an alternative ratio has been proposed called bone mineral apparent density [BMAD = BMC/(Ap)3/2]. However, bone size is not the only confounding variable associated with BMC. Others include age, sex, body size, and maturation. To assess the dimensional relationship between BMC and projected bone area, independent of other confounding variables, we proposed and fitted a proportional allometric model to the BMC data of the L2-L4 vertebrae from a previously published study. The projected bone area exponents were greater than unity for both boys (1.43) and girls (1.02), but only the boy's fitted exponent was not different from that predicted by geometric similarity (1.5). Based on these exponents, it is not clear whether bone mass acquisition increases in proportion to the projected bone area (Ap) or an estimate of projected bone volume (Ap)3/2. However, by adopting the proposed methods, the analysis will automatically adjust BMC for differences in projected bone size and other confounding variables for the particular population being studied. Hence, the necessity to speculate as to the theoretical value of the exponent of Ap, although interesting, becomes redundant