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Selective Laser Sintering of Passive Dynamic Ankle-Foot Orthoses
Passive dynamic ankle-foot orthoses (AFO’s) are used to improve gait performance in
those with various neuromuscular disorders. An important design characteristic of passive
dynamic AFOs is the storage and release of elastic energy within its structure to help satisfy the
energetic demands of walking. Thus, minimizing energy dissipation through internal friction is a
fundamental criterion for selecting the appropriate AFO material. This study compared the
mechanical damping of a carbon-fiber AFO to three geometrically identical AFO’s fabricated
using selective laser sintering with different materials. Mechanical damping characteristics
ranked the materials as Nylon 11 (best), followed by DuraformTM PA and DuraformTM GF
(worst).Mechanical Engineerin
Barium alginate capsules for 3D immobilisation of living cells: morphology, membrane properties and permeability
Encapsulation in a barium alginate membrane is a promising strategy to obtain a three dimensional culture of living cells: membrane properties are crucial for a realistic clinical application. A one-step encapsulation technique, recently developed for controlled release of boar semen, was employed to prepare barium alginate and protamine-alginate membranes: permeability to two model molecules (haemoglobin and glucose) was evaluated. Capsules were evaluated for technological properties and scanning electron microscopy was used to examine the external morphology of the capsules and the 3D distribution of the cells within the core. The results indicate that 3D arrangement and cell shape are maintained, capsule dimensions and mechanical properties can be modulated, as well as their permeability to model molecules such as haemoglobin and glucose
Fabrication of Ankle-Foot Orthoses using Selective Laser Sintering Technology
Passive dynamic ankle-foot orthoses (AFOs) are often prescribed to improve gait performance for those with various neuromuscular disorders. Designs and materials used for AFOs range from simple polypropylene braces to advanced custom carbon fiber dynamic AFOs that passively store and release mechanical energy during gait. AFO designs vary in the shape and length of the foot component as well as the stiffness and length of the tibial component, depending on the desired functional outcomes. However, the current fabrication technology is not ideally suited for refined customization of AFO characteristics to optimize performance, or for rapid lowcost, high volume manufacturing and global distribution.
A promising engineering solution for producing customized dynamic AFOs is the application of Selective Laser Sintering (SLS), which is a versatile manufacturing technology that provides advantages over traditional methods and has already been successfully used to fabricate prosthetic sockets for lower limb amputees (e.g., Faustini et al., 2006). Thus, the primary objective of this study was to explore the feasibility of using an SLSbased design, analysis and manufacturing framework to produce subject-specific passive dynamic AFOs in a cost-effective manner
Association between a single measurement of progesterone and cortisol blood concentrations at two to one week before parturition, and number of fetuses in the Teramana goat
The Teramana goat is an at-risk breed, needing population protection and programs to increase their
numbers. The first step for a population increase is the best management of reproduction, leading to an as
high as possible number of healthy and viable kids born. To this purpose, beside the optimization of mating,
the best possible management of pregnancy and parturition is mandatory. The goat is a prolific farm animal
in which single, double, or triple ovulations can occur, leading to singleton, twin or triple pregnancies, and
the birth of multiple kids. Twins and triplets are associated to increased risk for perinatal mortality and need
a special surveillance and possible assistance at birth. Knowledge of the number of fetuses that have to be
delivered from each goat could be a practical tool for a better management of parturition. Among the methods
to define the number of fetuses in the goat, the measurement of blood progesterone (P4) concentrations have
provided inconsistent results. Therefore, the present study was aimed to assess the possible association between
the maternal concentrations of plasma P4 and cortisol (C), two hormones possibly associated to the number of
fetuses, measured only once at about two to one week before parturition in Teramana goats, and the number
of fetuses. The results, obtained from 23 does, showed that both plasma P4 and C are higher in does bearing
multiple fetuses than does with singleton pregnancies. However, the single measurement of plasma C, but not
P4, two to one week before the expected parturition in the Teramana goat is useful to distinguish between
does bearing singleton and triplet pregnancies for a better surveillance and assistance at delivery. Therefore,
it could represent a tool for the best management of reproduction in a breed population at risk for extinctio
Role of Quantum Confinement in Luminescence Efficiency of Group IV Nanostructures
Experimental results obtained previously for the photoluminescence efficiency
(PL) of Ge quantum dots (QDs) are theoretically studied. A
- plot of PL versus QD diameter () resulted in an
identical slope for each Ge QD sample only when . We
identified that above 6.2 nm: due to a changing
effective mass (EM), while below 4.6 nm: due to
electron/ hole confinement. We propose that as the QD size is initially
reduced, the EM is reduced, which increases the Bohr radius and interface
scattering until eventually pure quantum confinement effects dominate at small
Variations of the spectral index of dust emissivity from Hi-GAL observations of the Galactic plane
Original article can be found at: http://www.aanda.org/ Copyright The European Southern ObservatoryContext. Variations in the dust emissivity are critical for gas mass determinations derived from far-infrared observations, but also for separating dust foreground emission from the Cosmic Microwave Background (CMB). Hi-GAL observations allow us for the first time to study the dust emissivity variations in the inner regions of the Galactic plane at resolution below 1°. Aims. We present maps of the emissivity spectral index derived from the combined Herschel PACS 160 μm, SPIRE 250 μm, 350 μm, and 500 μm data, and the IRIS 100 μm data, and we analyze the spatial variations of the spectral index as a function of dust temperature and wavelength in the two science demonstration phase Hi-GAL fields, centered at l = 30° and l = 59°. Methods. Applying two different methods, we determine both dust temperature and emissivity spectral index between 100 and 500 μm, at an angular resolution (θ) of 4'. Results. Combining both fields, the results show variations of the emissivity spectral index in the range 1.8–2.6 for temperatures between 14 and 23 K. The median values of the spectral index are similar in both fields, i.e. 2.3 in the range 100–500 μm, while the median dust temperatures are equal to 19.1 K and 16.0 K in the l = 30° and l = 59° field, respectively. Statistically, we do not see any significant deviations in the spectra from a power law emissivity between 100 and 500 μm. We confirm the existence of an inverse correlation between the emissivity spectral index and dust temperature, found in previous analyses.Peer reviewe
Kit Radicaux Libres, a Biological Application for Monitoring Oxidative Stress in Pigs
Kit Radicaux Libres (KRL) test is a biological application, successfully applied on humans, helpful for the study of the total antiradical activity. In the present work, the first objective was to test on a subset of pig blood samples in order to determine the maximum time of storage able to provide reliable results. Blood samples were collected from 46 piglets and determinations were carried out on the blood samples after three h from collection (T1) and thereafter at 24 (T2) and 48 (T3) h. Successively blood samples from 313 piglets (171 castrated males and 142 females) were collected and analysed in order to determine reference intervals. Results are expressed as half-haemolysis time (HT50 in min), that is a reference point for blood susceptibility to free radical attack. Our findings showed that for samples analysed at T1 and T2 there were no significant changes but significantly increased values (P<0.05) were obtained when samples were analysed after 48 h from collection, underlining biological and analytical interference due to the hemolysis of the samples. The reference values found in the subjects, expressed as ET AL50 were 46.6-68.7 min (males) and 52.5-86.8 min (females) in RBC, 59.8-93.6 min (males) and 70.5-113.0 (females) in whole blood. In conclusion, a prolonged time (till +48 h) caused haemolysis, therefore the use of freshly collected blood is strictly recommended. The reference values obtained are considered to represent valid reference ranges for healthy pigs starting after weaning to 175 days of age under modern husbandry conditions
The pre-ZAMS nature of Mol160/IRAS23385+6053 confirmed by Spitzer
Determining the timeline for the formation of massive YSOs requires the
identification and characterisation of all the phases that a massive forming
YSO undergoes. It is of particular interest to verify the observability of the
phase in which the object is rapidly accreting while not yet igniting the
fusion of hydrogen that marks the arrival on the ZAMS. One of the candidate
prototypical objects for this phase is Mol160/IRAS23385+6053, which previous
studies suggest it could be in a pre-Hot Core stage. We further investigate
this issue by means of Spitzer imaging and spectroscopy in the 5-70 micron
range. The dense core of Mol160/IRAS23385+6053, which up to now had only been
detected at submm and mm wavelenghts has been revealed for the first time at 24
and 70 micron by Spitzer. The complete 24 micron -3.4 mm continuum cannot be
fitted with a standard model of a Zero-Age Main-Sequence (ZAMS) star embedded
in an envelope. A simple greybody fit yields a mass of 220 solar masses. The
luminosity is slightly in excess of 3000 solar luminosities, which is a factor
of 5 less than previous estimates when only IRAS fluxes were available between
20 and 100 micron. The source is under-luminous by the same factor with respect
to UCHII regions or Hot-Cores of similar circumstellar mass, and simple models
show that this is compatible with an earlier evolutionary stage. Spectroscopy
between 5 and 40 microns revelas typical PDR/PIR conditions, where the required
UV illumination may be provided by other sources revealed at 24 microns in the
same region, and which can be plausibly modeled as moderately embedded
intermediate-mass ZAMS stars. Our results strengthen the suggestion that the
central core in Mol160/IRAS23385+6053 is a massive YSO actively accreting from
its circumstellar envelope and which did not yet begin hydrogen fusion.Comment: Accepted by A&
Direct Estimate of Cirrus Noise in Herschel Hi-GAL Images
In Herschel images of the Galactic plane and many star forming regions, a
major factor limiting our ability to extract faint compact sources is cirrus
confusion noise, operationally defined as the "statistical error to be expected
in photometric measurements due to confusion in a background of fluctuating
surface brightness". The histogram of the flux densities of extracted sources
shows a distinctive faint-end cutoff below which the catalog suffers from
incompleteness and the flux densities become unreliable. This empirical cutoff
should be closely related to the estimated cirrus noise and we show that this
is the case. We compute the cirrus noise directly, both on Herschel images from
which the bright sources have been removed and on simulated images of cirrus
with statistically similar fluctuations. We connect these direct estimates with
those from power spectrum analysis, which has been used extensively to predict
the cirrus noise and provides insight into how it depends on various
statistical properties and photometric operational parameters. We report
multi-wavelength power spectra of diffuse Galactic dust emission from Hi-GAL
observations at 70 to 500 microns within Galactic plane fields at l= 30 degrees
and l= 59 degrees. We find that the exponent of the power spectrum is about -3.
At 250 microns, the amplitude of the power spectrum increases roughly as the
square of the median brightness of the map and so the expected cirrus noise
scales linearly with the median brightness. Generally, the confusion noise will
be a worse problem at longer wavelengths, because of the combination of lower
angular resolution and the rising power spectrum of cirrus toward lower spatial
frequencies, but the photometric signal to noise will also depend on the
relative spectral energy distribution of the source compared to the cirrus.Comment: 4 pages (in journal), 3 figures, Astronomy and Astrophysics, accepted
for publication 13 May 201
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