9 research outputs found
The IDvIP Trial: A two-centre randomised double-blind controlled trial comparing intramuscular diamorphine and intramuscular pethidine for labour analgesia
<p>Abstract</p> <p>Background</p> <p>Intramuscular pethidine is routinely used throughout the UK for labour analgesia. Studies have suggested that pethidine provides little pain relief in labour and has a number of side effects affecting mother and neonate. It can cause nausea, vomiting and dysphoria in mothers and can cause reduced fetal heart rate variability and accelerations. Neonatal effects include respiratory depression and impaired feeding. There are few large studies comparing the relative side effects and efficacy of different opioids in labour. A small trial comparing intramuscular pethidine with diamorphine, showed diamorphine to have some benefits over pethidine when used for labour analgesia but the study did not investigate the adverse effects of either opioid.</p> <p>Methods</p> <p>The Intramuscular Diamorphine versus Intramuscular Pethidine (IDvIP) trial is a randomised double-blind two centre controlled trial comparing intramuscular diamorphine and pethidine regarding their analgesic efficacy in labour and their side effects in mother, fetus and neonate. Information about the trial will be provided to women in the antenatal period or in early labour. Consent and recruitment to the trial will be obtained when the mother requests opioid analgesia. The sample size requirement is 406 women with data on primary outcomes. The maternal primary outcomes are pain relief during the first 3 hours after trial analgesia and specifically pain relief after 60 minutes. The neonatal primary outcomes are need for resuscitation and Apgar Score <7 at 1 minute. The secondary outcomes are an additional measure of pain relief, maternal sedation, nausea and vomiting, maternal oxygen saturation, satisfaction with analgesia, whether method of analgesia would be used again, use of Entonox, umbilical arterial and venous pH, fetal heart rate, meconium staining, time from delivery to first breath, Apgar scores at 5 mins, naloxone requirement, transfer to neonatal intensive care unit, neonatal haemoglobin oxygen saturation at 30, 60, 90, and 120 mins after delivery, and neonatal sedation and feeding behaviour during first 2 hours.</p> <p>Discussion</p> <p>If the trial demonstrates that diamorphine provides better analgesia with fewer side effects in mother and neonate this could lead to a change in national practice and result in diamorphine becoming the preferred intramuscular opioid for analgesia in labour.</p> <p>Trial Registration</p> <p><a href="http://www.controlled-trials.com/ISRCTN14898678">ISRCTN14898678</a></p> <p>Eudra No: 2006-003250-18, REC Reference No: 06/Q1702/95, MHRA Authorisation No: 1443/0001/001-0001, NIHR UKCRN reference 6895, RfPB grant PB-PG-0407-13170_IR5</p
Hybrid Carbon Silica Nanofibers through SolâGel Electrospinning
A controlled solâgel synthesis
incorporated with electrospinning
is employed to produce polyacrylonitrileâsilica (PANâsilica)
fibers. Hybrid fibers are obtained with varying amounts of silica
precursor (TEOS in DMF catalyzed by HCl) and PAN. Solution viscosity,
conductivity, and surface tension are found to relate strongly to
the electrospinnability of PANâsilica solutions. TGA and DSC
analyses of the hybrids indicate strong intermolecular interactions,
possibly between the âOH group of silica and âCN of
PAN. Thermal stabilization of the hybrids at 280 °C followed
by carbonization at 800 °C transforms fibers to carbonâsilica
hybrid nanofibers with smooth morphology and diameter ranging from
400 to 700 nm. FTIR analysis of the fibers confirms the presence of
silica in the as-spun as well as the carbonized material, where the
extent of carbonization is also estimated by confirming the presence
of âCî»C and âCî»O peaks in the carbonized
hybrids. The graphitic character of the carbonâsilica fibers
is confirmed through Raman studies, and the role of silica in the
disorder of the carbon structure is discussed
Hybrid SilicaâPVA Nanofibers via SolâGel Electrospinning
We report on the synthesis of polyÂ(vinyl alcohol) (PVA)âsilica
hybrid nanofibers via solâgel electrospinning. Silica is synthesized
through acid catalysis of a silica precursor (tetraethyl orthosilicate
(TEOS) in ethanolâwater), and fibers are obtained by electrospinning
a mixture of the silica precursor solution and aqueous PVA. A systematic
investigation on how the amount of TEOS, the silicaâPVA ratio,
the aging time of the silica precursor mixture, and the solution rheology
influence the fiber morphology is undertaken and reveals a composition
window in which defect-free hybrid nanofibers with diameters as small
as 150 nm are obtained. When soaked overnight in water, the hybrid
fibers remain intact, essentially maintaining their morphology, even
though PVA is soluble in water. We believe that mixing of the silica
precursor and PVA in solution initiates the participation of the silica
precursor in cross-linking of PVA so that its âOH group becomes
unavailable for hydrogen bonding with water. FTIR analysis of the
hybrids confirms the disappearance of the âOH peak typically
shown by PVA, while formation of a bond between PVA and silica is
indicated by the SiâOâC peak in the spectra of all the
hybrids. The ability to form cross-linked nanofibers of PVA using
thermally stable and relatively inert silica could broaden the scope
of use of these materials in various technologies
Fibrillar Structure of Methylcellulose Hydrogels
It is well established that aqueous
solutions of methylcellulose
(MC) can form hydrogels on heating, with the rheological gel point
closely correlated to the appearance of optical turbidity. However,
the detailed gelation mechanism and the resulting gel structure remain
poorly understood. Herein the fibrillar structure of aqueous MC gels
was precisely quantified with a powerful combination of (real space)
cryogenic transmission electron microscopy (cryo-TEM) and (reciprocal
space) small-angle neutron scattering (SANS) techniques. The cryo-TEM
images reveal that MC chains with a molecular weight of 300â000
g/mol associate into fibrils upon heating, with a remarkably uniform
diameter of 15 ± 2 nm over a range of concentrations. Vitrified
gels also exhibit heterogeneity in the fibril density on the length
scale of hundreds of nanometers, consistent with the observed optical
turbidity of MC hydrogels. The SANS curves of gels exhibit no characteristic
peaks or plateaus over a broad range of wavevector, <i>q</i>, from 0.001â0.2 Ă
<sup>â1</sup>. The major feature
is a change in slope from <i>I</i> ⌠<i>q</i><sup>â1.7</sup> in the intermediate <i>q</i> range
(0.001 â 0.01 Ă
<sup>â1</sup>) to <i>I</i> ⌠<i>q</i><sup>â4</sup> above <i>q</i> â 0.015 Ă
<sup>â1</sup>. The fibrillar nature
of the gel structure was confirmed by fitting the SANS data consistently
with a model based on the form factor for flexible cylinders with
a polydisperse radius. This model was found to capture the scattering
features quantitatively for MC gels varying in concentration from
0.09â1.3 wt %. In agreement with the microscopy results, the
flexible cylinder model indicated fibril diameters of 14 ± 1
nm for samples at elevated temperatures. This combination of complementary
experimental techniques provides a comprehensive nanoscale depiction
of fibrillar morphology for MC gels, which correlates very well with
macro-scale rheological behavior and optical turbidity previously
observed for such systems
Toxic Epidermal Necrolysis in Recessive Dystrophic Epidermolysis Bullosa following Bone Marrow Transplantation
New constraints on the last aragoniteâcalcite sea transition from early Jurassic ooids
Isotope ratios of H, C, and O in CO2 and H2O of the Martian atmosphere
Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and O-18/O-16 in water and C-13/C-12, O-18/O-16, O-17/O-16, and (CO)-C-13-O-18/(CO)-C-12-O-16 in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established similar to 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing