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Background: The timing of the circulatory determination of death for organ donation presents a medical and ethical challenge. Concerns have been raised about the timing of electrocerebral inactivity in relation to the cessation of circulatory function in organ donation after cardio-circulatory death. Nonprocessed electroencephalographic (EEG) measures have not been characterized and may provide insight into neurological function during this process. Methods: We assessed electrocortical data in relation to cardiac function after withdrawal of life-sustaining therapy and in the postmortem period after cardiac arrest for four patients in a Canadian intensive care unit. Subhairline EEG and cardio-circulatory monitoring including electrocardiogram, arterial blood pressure (ABP), and oxygen saturation were captured. Results: Electrocerebral inactivity preceded the cessation of the cardiac rhythm and ABP in three patients. In one patient, single delta wave bursts persisted following the cessation of both the cardiac rhythm and ABP. There was a significant difference in EEG amplitude between the 30-minute period before and the 5-minute period following ABP cessation for the group, but we did not observe any well-defined EEG states following the early cardiac arrest period. Conclusions: In a case series of four patients, EEG inactivity preceded electrocardiogram and ABP inactivity during the dying process in three patients. Further study of the electroencephalogram during the withdrawal of life sustaining therapies will add clarity to medical, ethical, and legal concerns for donation after circulatory determined death.
To determine the incidence of high jugular bulb in a group of patients with definite Ménière's disease, and to investigate whether the position or size of the jugular bulb is significantly different in the affected ear than in the unaffected ear.
Retrospective review of patient charts, audiograms, and computed tomography scans to determine the position and size of the jugular bulb in the affected and contralateral ears, as well as other abnormalities.
High jugular bulb was found in 57.1 per cent of affected ears. Encroachment of the cochlear and vestibular aqueducts was apparent in 39.3 per cent and 35.7 per cent, respectively, of affected ears. Diverticulum and dehiscence were observed in 28.6 per cent of affected ears. High jugular bulb was significantly associated with encroachment of the cochlear aqueduct (p = 0.003).
The mediolateral and anteroposterior position of the jugular bulb determines encroachment of the surrounding structures. An abnormal position is postulated to contribute to the development of Ménière's disease.
We present the initial performance of the Gaia Radial Velocity Spectrometer, providing an overview of its performance, which is essentially nominal in terms of spectral resolution, throughput and operation, except for the presence of unexpectedly high levels of scattered background. This is mainly Solar in origin, and reduces the limiting magnitude for radial velocity measurements by ∼1 magnitude to V ∼ 16. Radial velocity calibration accuracies are compliant with requirements.
During the five years of the mission, the Gaia spectrograph, the Radial Velocity
Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude
V ~ 17–18. This talk presents: (i) the system which is currently developed within
the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the
spectra and to derive the radial and rotational velocities, (ii) the RVS expected
performances and (iii) scientific returns.
Some fast food restaurants have introduced a trade embargo on beef sold through livestock markets on the grounds that welfare standards associated with live auction markets are worse than standards associated with direct sale to abattoirs. The current study examined the handling difficulties and welfare standards at 24 UK cattle and calf markets, and comparisons were made according to class of animal (mainly store or finished) and according to throughput of the market, <100 livestock units (LSU) per week, 100–300 LSU per week and >300 LSU per week. Handling problems examined included refusal to move, balking, slips, falls, impacts, inappropriate handling such as excessive use of a stick, hazardous jumping and confusion while loading onto vehicles. The most common difficulties were impacts, slips and falls during grading and when putting cattle up to the sale ring. Slipping was also common in finished cattle while they were in the ring, and they were prone to impacts when returning to a holding pen. Refusing to load onto vehicles after the sale was common in both finished and store cattle. Calves were prone to going down on their knees when moving onto the tailboards of vehicles. Of the markets, 0·47 had potential bruising or impact points in the grading facilities and 0·67 of the markets did not have a way of ensuring that legs did not get trapped between gates and gateposts if cattle attempted to jump out of a holding pen. In most other respects the prevalence of weaknesses in the facilities and problems during handling was low.
Some meat retailers have introduced a trade embargo on fat lambs sold through livestock markets on the grounds that welfare standards associated with live auction markets are said to be worse than standards associated with direct sale to abattoirs. The current study examined the handling difficulties and welfare standards at 24 UK livestock markets. Comparisons were made according to class of animal (store, fat, breeding animals, etc.) and throughput of the market: <100 livestock units (LU) per week, 100–300 LU per week and >300 LU per week. Handling problems examined included refusal to move, balking, slips, falls, impacts, isolation leading to apparent distress, confusion while loading onto vehicles and inappropriate handling such as wool pulling. The overall prevalence of each handling problem was low (usually <0·05 of the sheep). The most common difficulties were impacts, slips and falls when grading fat lambs, and confusion or refusal to load onto the vehicles after the sale in ewes. Store lambs were generally easier to handle than fat lambs. They were less prone to refusing to move, balking, impacts, slips and falls. In fat lambs, slips and falls during grading were more common at small markets, while at larger markets there were more impacts, slips and falls during selling. Confusion during loading onto vehicles after the sale was more common in breeding ewes and rams, and at small markets. Projections in the corridors that were considered to be potential bruising or impact points were found in 0·33 of the markets and 0·71 did not have a way of ensuring that legs could not get trapped between gates and gateposts if sheep attempted to jump out of a holding pen. In most other respects the prevalence of problems with the facilities and during handling was low and it was concluded that a trade embargo on selling fat lambs in markets might not be justified.
Background and objective: A study was designed to utilise the resources of our computerised anaesthesia record keeping system to assess the attributable effects of increased preoperative creatinine (>1.3 mg dL−1) on outcome in patients undergoing non-cardiac surgery.
Methods: This retrospective study was based on data sets of 58 458 patients recorded with a computerised anaesthesia record keeping system over a period of 4 yr at a tertiary care university hospital. Cases were defined as patients with a preoperative creatinine >1.3 mg dL−1; controls (creatinine ≤1.3 mg dL−1) were selected and automatically matched according to several parameters (ASA physical status, high risk and urgency of surgery, age and gender) in a stepwise fashion. Main outcome measures were hospital mortality and the incidence of intraoperative cardiovascular events.
Results: Three-thousand-and-twenty-eight patients (5.2%) had preoperative creatinine values >1.3 mg dL−1. Matching was successful for 54.5% of the cases, leading to 1649 cases (mean creatinine 3.3 ± 2.2 mg dL−1) and 1649 controls (1.0 ± 0.2 mg dL−1). The crude mortality rates for the cases and matched controls were 2.2% (n = 36) and 0.9% (n = 15), respectively (P = 0.003). Intraoperative cardiovascular events were found in 30.1% of the patients (n = 496) and in 28.3% of the matched controls (n = 466; P = 0.25, power = 0.46). Using logistic regression analyses a significant association between preoperative increased creatinine and hospital mortality was found (odds ratio 2.62; 95% confidence interval [1.39; 4.93]).
Conclusions: An increased preoperative serum creatinine in patients undergoing non-cardiac surgery is associated with an increased perioperative risk, but not with a higher incidence of intraoperative cardiovascular events.
Combinatorial experiments provide a means of generating large amounts of experimental data; however that does not necessarily lead to high throughput interpretation of that data. In this paper we provide a brief summary of how one can use informatics techniques to accelerate data interpretation from high throughput experiments. We provide examples from high throughput nanoindentation and diffraction experiments.
Objectives: To determine the long-term outcomes and risk factors for, reintervention after balloon dilation of congenital aortic stenosis in children aged 6 months or older. Background: Although balloon dilation of congenital aortic stenosis has become a primary therapeutic strategy, few data are available regarding long-term outcomes. Methods: We carried out a retrospective review of 87 children who had undergone balloon dilation of the aortic valve at median age of 6.9 years. Results: The procedure was completed in 98% of the children, with an average reduction in the gradient across the valve of 64 ± 28%, and without mortality. Of the children, 76 had been followed for a mean of 6.3 ± 4.2 years. Reintervention on the aortic valve was required in 32 children, with 12 undergoing reintervention within 6 months, with 1 death. Another patient had died over the period of follow-up due to a non-cardiac event. Estimated freedom from reintervention was 86% at 1 year, 67% at 5 years, and 46% at 12 years. Parametric modeling of the hazard function showed a brief early phase of increased risk, superimposed on an ongoing constant risk. The only incremental risk factor for the early phase was a residual gradient immediately subsequent to the procedure greater than 30 mmHg. Incremental risk factors for the constant phase included the presence of symmetric valvar opening, and greater than moderate regurgitation immediately after dilation. Conclusion: Long-term survival was excellent, albeit that the need for further reintervention was high due to the palliative nature of the procedure.
Objectives: We sought to determine trends, and outcomes, for a cohort of patients with pulmonary atresia with intact ventricular septum born between 1965 and 1998. Background: Pulmonary atresia with intact ventricular septum is a complex lesion that remains a therapeutic challenge, particularly regarding the suitability for biventricular repair. Methods: We identified 210 consecutive patients, and reviewed their medical records, initial angiograms, and echocardiograms, along with the relevant surgical and pathology reports. Results: The mean initial Z-score for the diameter of the tricuspid valve was −0.99 ± 1.95, with Ebstein's malformation in 8%. A right ventricular dependent coronary arterial circulation was found in 23%. The proportion of patients who received treatment increased over time, although placement of an arterial shunt was the predominant initial procedure throughout the experience. At the last follow-up, 107 patients had not reached the planned final stage of their repair, and 79% of these had died. Of the 103 reaching the final stage of planned repair, 58 had undergone attempted biventricular repair, with 34% dying; 14 had undergone attempted one and a half ventricular repair, with 7% dying, and 31 had undergone attempted functionally univentricular repair, with 10% dying. Overall, survival was 57% at the age of 1 year, 48% at 5 years, and 43% at 10 years. Survival improved over time, with survival of 75% at 1 year, and 67% at 5 years, for patients born between 1992 and 1998. An earlier date of birth, the presence of Ebstein's malformation, and prematurity were all significant independent factors associated with decreased survival. A greater severity of coronary arterial abnormalities was significantly associated with a greater likelihood of left ventricular dysfunction during follow-up. Conclusions: The outcomes for patients born with pulmonary atresia with intact ventricular septum have improved over time, albeit that careful initial management, and better selection, is still indicated for those planned to undergo biventricular repair.
This study focuses on a Co-based nanocrystalline alloy (Co84.55Fe4.45Zr7B4) with potential for long-term high temperature use. As an indication of their performance, core losses were measured on toroidal samples using a Walker AC permeameter over a frequency range of 0.1 to 500 kHz, at induction amplitudes of 100, 300, and 500 mT, and temperatures from 22 to 300°C. For a given frequency and maximum induction amplitude, the losses were invariant as a function of measurement temperature. Vibrating sample magnetometry provided the magnetization and hysteretic losses as a function of temperature. As the temperature of the alloy was raised to 300°C from room temperature, the saturation magnetization (120 emu/g)was reduced by less than 15%. A toroid was aged at 300°C for up to 300 hours and core loss measured as a function of aging time at the previously mentioned frequencies and induction amplitudes. The losses were invariant over the aging time.
Transient ionizing radiation fields have been observed to cause substantial optical loss in undoped LiNbO3 crystals operating at 1.06 microns. This loss is slow to recover and makes the selection of this material for Q-switch applications in radiation environments unfeasible. We have studied the effects of Mg doping on the radiation response of LiNbO3 crystals and have investigated the optical luminescence of doped and undoped samples. Our results indicate a strong correlation between crystal defects, formed primarily during crystal growth, and the radiation-induced optical loss exhibited by these materials. These findings have enabled us to produce radiation-hard LiNbO3 crystals for use in high gamma-field environments.
We describe a > 100 Watt broadband THz source that takes advantage of the relativistic enhancement of the radiation from accelerating electrons according to the formula assigned the name of Sir Joseph Larmor[1, 2]. This is in contrast to the typical 1 milliwatt sources available in a laboratory. Specifically, for relativistic electrons the emission is enhanced by the fourth power of the increase in mass. Thus for 100 MeV electrons, for which the mass increases by a factor of ∼ 200, the enhancement is > 109. The experiments use a new generation of light source called an energy recovery linac (ERL) , in which bunches of electrons circulate once, but in which their energy is recovered. In such a machine the electron bunches can be very much shorter than those, say, in storage rings or synchrotrons.
The Jefferson Lab facility operates in new limits of emission from relativistic particles involving both multiparticle coherence and near-field emission in which the velocity (Coulomb) term in the classical electrodynamical theory becomes as important as the acceleration term (synchrotron radiation).
The sub-picosecond pulses of light offer unique capabilities in 2 specific areas, namely time-resolved dynamics, and imaging. High resolution THz spectroscopy has recently revealed sharp vibrational modes for many materials including malignant tissue, proteins, DNA, pharmaceuticals and explosive materials. Energetically the THz range embraces superconducting bandgaps, and regions of intense interest in the understanding of systems in which correlated motions of electrons are important, such as colossal magneto-resistive and high-Tc materials. The very high power levels of the new source will allow non-linear effects to be observed as well as the creation of novel states of materials, including electric-field driven localization. We will give examples of existing work in these areas and present opportunities afforded by the new source.
Boron carbonitride nanotubes (BCNNTs) were grown with high yield by arc discharge without catalyst particles or pre-grown template nanostructures. Two types of nanotubes (NTs) were formed: thin NTs with diameters of 10–15 nm and thick NTs with diameters of 25–50 nm, all multiwall. Transmission electron microscopy, electron energy loss spectroscopy, and Raman spectroscopy analyses indicate that the thin NTs are carbon NTs (CNTs) while the thick NTs are BCNNTs wrapped around CNTs. The growth kinetic appears to be faster for CNTs than for BCNNTs. Through the concerted substitution of B and N for C in the in situ grown CNTs, template growth of BCNNTs follows the CNTs growth without causing topological changes.
The majority of high-efficiency space solar cells being produced today are based on multi-junction devices of lattice-matched III-V materials. An alternative which has been receiving an increasing amount of attention is the lattice mis-matched or metamorphic approach to multi-junction cell development. In the metamorphic triple junction cell under development by ERI and its partners, the InGaAs junction (bottom cell) of the three-cell stack is the current limiting entity, due to the current matching which must be maintained through the device. This limitation may be addressed through the incorporation of InAs quantum dot array into the depletion region of an InGaAs cell. The InAs quantum dots in the InGaAs cell will provide sub-gap absorption and thus improve its short circuit current. This cell could then be integrated into the three-cell stack to achieve a space solar cell whose efficiency exceeds current state-of-the-art standards. A theoretical estimate predicts that a InGaAlP(1.95eV)/InGaAsP(1.35 eV)/InGaAs(1.2 eV) triple junction cell incorporating quantum dots to improve the bottom cell current would have an efficiency exceeding 40%. In addition, theoretical estimates have demonstrated that the use of quantum dot structures may also hold other cell benefits such as improved temperature coefficients and better radiation tolerance, which are especially important for utilization in space. As a first step towards achieving that goal, we have initiated the development of InAs quantum dots on lattice-mismatched InGaAs (1.2 eV bandgap) grown epitaxially on GaAs by metallorganic vapor phase epitaxy (MOVPE). These quantum dots have been characterized via photoluminescence (PL) and atomic force microscopy (AFM). A correlation exists between the quantum dot size and resulting optical band structure and can be controlled via the synthesis parameters. Quantum dots were incorporated into prototype InGaAs devices. A comparison of the resulting photovoltaic efficiency under simulated 1 sun intensity and air mass zero (AM0) illumination and spectral response demonstrated that an improvement in the long-wavelength photoconversion efficiency was achieved through the incorporation of the InAs quantum dots.
Good practical adhesion of sputter-deposited Cu is achieved to poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) surfaces at short treatment times of vacuum UV (VUV) photo-oxidation downstream from Ar microwave (MW) plasma. Factors contributing to the adhesion include: (1) an improvement in wettability as observed by water contact angle measurements; (2) surface roughening; (3) defluorination of the surface; (4) cross-linking at the surface and (5) incorporation of oxygen as CF-O-CF2, CF2-O-CF2 and CF-O-CnF2n+1 moieties. With long treatment times, a cohesive failure occurred within the modified PFA and not at the Cu-PFA interface due to extensive chain scission weakening its mechanical properties.
Synthesis, mechanical testing, and modeling have been performed for a carbon nanotube material in which the nanotubes are functionalized with variable stiffness tethers (VST) capable of cross-linking the nanotubes. Tests using nanoindentation indicated a six-fold enhancement in the storage modulus when comparing the base material (the cross-linking agent with no nanotubes) to the composite (functionalized nanotube material) that contained 5.3 wt% of nanotubes. To understand how crosslinking the nanotubes may further alter the stiffness, a model of the system was constructed using nanotubes crosslinked with the VST. The model predicted that for a composite with 5 wt% nanotubes at random orientations, crosslinked with the VST, the bulk Young's modulus was reduced to 30% that of the non-crosslinked equivalent.