892 research outputs found
Early identification of the difficult airway from orbital deformity
"We report an adult patient presenting for surgery with hidden marked orbital exenteration (Figures 1, 2). The patient had history of resected left orbital neoplasm that remained concealed under an eye patch during preoperative physical examination and presentation to the operating room. Face mask ventilation proved impossible after anesthetic induction. Removal of the eye patch revealed a large facial orbital floor defect from exenteration of the orbit floor and the patient immediately underwent endotracheal intubation. Following the procedure, postoperative respiratory insufficiency required additional airway support. Emergent placement of a laryngeal mask airway provided adequate ventilation."--CaseJulie M. Marshall, Noah J. Timko (Department of Anesthesiology and Perioperative Medicine, University of Missouri)Includes bibliographical reference
Structural characterization of magnetoferritin
Physico-chemical characterization of biomacromolecule magnet of erritin in terms of morphology, structural and magnetic properties shows that iron oxides can be efficiently loaded into apoferritin molecules, preserving its native, bio-compatible structure. At the same time, such loading affects the morphology of the protein shell
Does case misclassification threaten the validity of studies investigating the relationship between neck manipulation and vertebral artery dissection stroke? No
Background: The purported relationship between cervical manipulative therapy (CMT) and stroke related to vertebral artery dissection (VAD) has been debated for several decades. A large number of publications, from case reports to case–control studies, have investigated this relationship. A recent article suggested that case misclassification in the case–control studies on this topic resulted in biased odds ratios in those studies. Discussion: Given its rarity, the best epidemiologic research design for investigating the relationship between CMT and VAD is the case–control study. The addition of a case-crossover aspect further strengthens the scientific rigor of such studies by reducing bias. The most recent studies investigating the relationship between CMT and VAD indicate that the relationship is not causal. In fact, a comparable relationship between vertebral artery-related stroke and visits to a primary care physician has been observed. The statistical association between visits to chiropractors and VAD can best be explained as resulting from a patient with early manifestation of VAD (neck pain with or without headache) seeking the services of a chiropractor for relief of this pain. Sometime after the visit the patient experiences VAD-related stroke that would have occurred regardless of the care received. This explanation has been challenged by a recent article putting forth the argument that case misclassification is likely to have biased the odds ratios of the case–control studies that have investigated the association between CMT and vertebral artery related stroke. The challenge particularly focused on one of the case–control studies, which had concluded that the association between CMT and vertebral artery related stroke was not causal. It was suggested by the authors of the recent article that misclassification led to an underestimation of risk. We argue that the information presented in that article does not support the authors’ claim for a variety of reasons, including the fact that the assumptions upon which their analysis is based lack substantiation and the fact that any possible misclassification would not have changed the conclusion of the study in question. Conclusion: Current evidence does not support the notion that misclassification threatens the validity of recent case–control studies investigating the relationship between CMT and VAD. Hence, the recent re-analysis cannot refute the conclusion from previous studies that CMT is not a cause of VAD.https://doi.org/10.1186/s12998-016-0124-
Chloroplast-encoded chlB is required for light-independent protochlorophyllide reductase activity in Chlamydomonas reinhardtii.
Extracting W Boson Couplings from the Production of Four Leptons
We consider the processes , including all possible charged lepton combinations, with
regard to measuring parameters characterizing the boson. We calculate at
what level these processes can be used to measure anamolous triple-boson
vertice coupling parameters for the cases of colliders at 500
and 1 center of mass energies.Comment: 13 pages,OCIP/C-93-
Near-infrared-actuated devices for remotely controlled drug delivery
A reservoir that could be remotely triggered to release a drug would enable the patient or physician to achieve on-demand, reproducible, repeated, and tunable dosing. Such a device would allow precise adjustment of dosage to desired effect, with a consequent minimization of toxicity, and could obviate repeated drug administrations or device implantations, enhancing patient compliance. It should exhibit low off-state leakage to minimize basal effects, and tunable on-state release profiles that could be adjusted from pulsatile to sustained in real time. Despite the clear clinical need for a device that meets these criteria, none has been reported to date to our knowledge. To address this deficiency, we developed an implantable reservoir capped by a nanocomposite membrane whose permeability was modulated by irradiation with a near-infrared laser. Irradiated devices could exhibit sustained on-state drug release for at least 3 h, and could reproducibly deliver short pulses over at least 10 cycles, with an on/off ratio of 30. Devices containing aspart, a fast-acting insulin analog, could achieve glycemic control after s.c. implantation in diabetic rats, with reproducible dosing controlled by the intensity and timing of irradiation over a 2-wk period. These devices can be loaded with a wide range of drug types, and therefore represent a platform technology that might be used to address a wide variety of clinical indications
Progress with the Upgrade of the SPS for the HL-LHC Era
The demanding beam performance requirements of the High Luminosity (HL-) LHC
project translate into a set of requirements and upgrade paths for the LHC
injector complex. In this paper the performance requirements for the SPS and
the known limitations are reviewed in the light of the 2012 operational
experience. The various SPS upgrades in progress and still under consideration
are described, in addition to the machine studies and simulations performed in
2012. The expected machine performance reach is estimated on the basis of the
present knowledge, and the remaining decisions that still need to be made
concerning upgrade options are detailed.Comment: 3 p. Presented at 4th International Particle Accelerator Conference
(IPAC 2013
Reductions in aircraft particulate emissions due to the use of Fischer–Tropsch fuels
The use of alternative fuels for aviation is likely to increase due to
concerns over fuel security, price stability, and the sustainability of fuel
sources. Concurrent reductions in particulate emissions from these
alternative fuels are expected because of changes in fuel composition
including reduced sulfur and aromatic content. The NASA Alternative Aviation
Fuel Experiment (AAFEX) was conducted in January–February 2009 to
investigate the effects of synthetic fuels on gas-phase and particulate
emissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced from
natural gas and coal feedstocks using the Fischer–Tropsch (FT) process, and
50% blends of both fuels were tested in the CFM-56 engines on a DC-8
aircraft. To examine plume chemistry and particle evolution with time,
samples were drawn from inlet probes positioned 1, 30, and 145 m downstream
of the aircraft engines. No significant alteration to engine performance was
measured when burning the alternative fuels. However, leaks in the aircraft
fuel system were detected when operated with the pure FT fuels as a result
of the absence of aromatic compounds in the fuel.
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Dramatic reductions in soot emissions were measured for both the pure FT
fuels (reductions in mass of 86% averaged over all powers) and blended
fuels (66%) relative to the JP-8 baseline with the largest reductions at
idle conditions. At 7% power, this corresponds to a reduction from 7.6 mg kg<sup>−1</sup>
for JP-8 to 1.2 mg kg<sup>−1</sup> for the natural gas FT fuel. At full
power, soot emissions were reduced from 103 to 24 mg kg<sup>−1</sup>
(JP-8 and natural gas FT, respectively). The alternative fuels also produced
smaller soot (e.g., at 85% power, volume mean diameters were reduced from
78 nm for JP-8 to 51 nm for the natural gas FT fuel), which may reduce their
ability to act as cloud condensation nuclei (CCN). The reductions in
particulate emissions are expected for all alternative fuels with similar
reductions in fuel sulfur and aromatic content regardless of the feedstock.
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As the plume cools downwind of the engine, nucleation-mode aerosols form.
For the pure FT fuels, reductions (94% averaged over all powers) in
downwind particle number emissions were similar to those measured at the
exhaust plane (84%). However, the blended fuels had less of a reduction
(reductions of 30–44%) than initially measured (64%). The likely
explanation is that the reduced soot emissions in the blended fuel exhaust
plume results in promotion of new particle formation microphysics, rather
than coating on pre-existing soot particles, which is dominant in the JP-8
exhaust plume. Downwind particle volume emissions were reduced for both the
pure (79 and 86% reductions) and blended FT fuels (36 and 46%) due to
the large reductions in soot emissions. In addition, the alternative fuels
had reduced particulate sulfate production (near zero for FT fuels) due to
decreased fuel sulfur content.
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To study the formation of volatile aerosols (defined as any aerosol formed as
the plume ages) in more detail, tests were performed at varying ambient
temperatures (−4 to 20 °C). At idle, particle number and volume
emissions were reduced linearly with increasing ambient temperature, with
best fit slopes corresponding to −8 × 10<sup>14</sup> particles
(kg fuel)<sup>−1</sup> °C<sup>−1</sup> for particle number emissions and
−10 mm<sup>3</sup> (kg fuel)<sup>−1</sup> °C<sup>−1</sup> for particle volume
emissions. The temperature dependency of aerosol formation can have large
effects on local air quality surrounding airports in cold regions.
Aircraft-produced aerosols in these regions will be much larger than levels
expected based solely on measurements made directly at the engine exit plane.
The majority (90% at idle) of the volatile aerosol mass formed as
nucleation-mode aerosols, with a smaller fraction as a soot coating.
Conversion efficiencies of up to 2.8% were measured for the partitioning
of gas-phase precursors (unburned hydrocarbons and SO<sub>2</sub>) to form volatile
aerosols. Highest conversion efficiencies were measured at 45% power
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