1,301 research outputs found
Do any of the following acts, which occurred during Iraq’s invasion and occupation of Kuwait, constitute crimes under the IHT Statute: (1) the removal of food, medical supplies, and medical equipment from Kuwait to Iraq; (2) the destruction of Kuwaiti assets and infrastructures; and (3) the destruction of Kuwaiti oil wells and oil refineries, and the deliberate release of oil into the Persian Gulf?
An injection and mixing element for delivery and monitoring of inhaled nitric oxide
Background Inhaled nitric oxide (NO) is a selective pulmonary vasodilator used primarily in the critical care setting for patients concurrently supported by invasive or noninvasive positive pressure ventilation. NO delivery devices interface with ventilator breathing circuits to inject NO in proportion with the flow of air/oxygen through the circuit, in order to maintain a constant, target concentration of inhaled NO. Methods In the present article, a NO injection and mixing element is presented. The device borrows from the design of static elements to promote rapid mixing of injected NO-containing gas with breathing circuit gases. Bench experiments are reported to demonstrate the improved mixing afforded by the injection and mixing element, as compared with conventional breathing circuit adapters, for NO injection into breathing circuits. Computational fluid dynamics simulations are also presented to illustrate mixing patterns and nitrogen dioxide production within the element. Results Over the range of air flow rates and target NO concentrations investigated, mixing length, defined as the downstream distance required for NO concentration to reach within ±5 % of the target concentration, was as high as 47 cm for the conventional breathing circuit adapters, but did not exceed 7.8 cm for the injection and mixing element. Conclusion The injection and mixing element has potential to improve ease of use, compatibility and safety of inhaled NO administration with mechanical ventilators and gas delivery devices
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Reversible Total Vision Loss Caused by Severe Metformin-associated Lactic Acidosis: A Case Report.
INTRODUCTION: Metformin is a biguanide used to treat diabetes mellitus (DM). Metformin-associated lactic acidosis (MALA) carries a high mortality and can occur in patients with renal failure from drug bioaccumulation. Reversible vision loss is a highly unusual, rarely reported complication of MALA. We present a case of a patient whose serum metformin concentration was unusually high and associated with vision loss.
CASE REPORT: A 60-year-old woman presented to an outside hospital emergency department with acute vision loss after being found at home confused, somnolent, and hypoglycemic, having last being seen normal two days prior. She reported vomiting and diarrhea during that time and a recently treated urinary tract infection. The visual loss resolved with continuous renal replacement therapy.
CONCLUSION: This novel case of a patient with Type II DM prescribed metformin and insulin who developed reversible vision loss while suffering from MALA highlights the potential for vision loss in association with MALA
Variability in uptake efficiency for pulsed versus constant concentration delivery of inhaled nitric oxide
BACKGROUND: Nitric oxide (NO) is currently administered using devices that maintain constant inspired NO concentrations. Alternatively, devices that deliver a pulse of NO during the early phase of inspiration may have use in optimizing NO dosing efficiency and in extending application of NO to long-term use by ambulatory, spontaneously breathing patients. The extent to which the amount of NO delivered for a given pulse sequence determines alveolar concentrations and uptake, and the extent to which this relationship varies with breathing pattern, physiological, and pathophysiological parameters, warrants investigation. METHODS: A mathematical model was used to analyze inhaled nitric oxide (NO) transport through the conducting airways, and to predict uptake from the alveolar region of the lung. Pulsed delivery was compared with delivery of a constant concentration of NO in the inhaled gas. RESULTS: Pulsed delivery was predicted to offer significant improvement in uptake efficiency compared with constant concentration delivery. Uptake from the alveolar region depended on pulse timing, tidal volume, respiratory rate, lung and dead space volume, and the diffusing capacity of the lung for NO (D(L)NO). It was predicted that variation in uptake efficiency with breathing pattern can be limited using a pulse time of less than 100Â ms, with a delay of less than 50Â ms between the onset of inhalation and pulse delivery. Nonlinear variation in uptake efficiency with D(L)NO was predicted, with uptake efficiency falling off sharply as D(L)NO decreased below ~50-60Â ml/min/mm Hg. Gas mixing in the conducting airways played an important role in determining uptake, such that consideration of bulk convection alone would lead to errors in assessing efficiency of pulsed delivery systems. CONCLUSIONS: Pulsed NO delivery improves uptake efficiency compared with constant concentration delivery. Optimization of pulse timing is critical in limiting intra- and inter-subject variability in dosing
Interpreting the seasonal cycles of atmospheric oxygen and carbon dioxide concentrations at American Samoa Observatory
We present seven years of atmospheric O2/N2 ratio and CO2 concentration data measured from flask samples collected at American Samoa. These data are unusual, exhibiting higher short-term variability, and seasonal cycles not in phase with other sampling stations. The unique nature of atmospheric data from Samoa has been noted previously from measurements of CO2, methyl chloroform, and ozone. With our O2 data, we observe greater magnitude in the short-term variability, but, in contrast, no clear seasonal pattern to this variability. This we attribute to significant regional sources and sinks existing for O2 in both hemispheres, and a dependence on both the latitudinal and altitudinal origins of air masses. We also hypothesize that some samples exhibit a component of "older" air, demonstrating recirculation of air within the tropics. Our findings could be used to help constrain atmospheric transport models which are not well characterized in tropical regions
4-aminopyridine toxicity: a case report and review of the literature.
INTRODUCTION: 4-Aminopyridine (4-AP) selectively blocks voltage-gated potassium channels, prolongs the action potential, increases calcium influx, and subsequently, enhances interneuronal and neuromuscular synaptic transmission. This medication has been studied and used in many disease processes hallmarked by poor neuronal transmission in both the central and peripheral nervous systems including: multiple sclerosis (MS), spinal cord injuries (SCI), botulism, Lambert-Eaton syndrome, and myasthenia gravis. It has also been postulated as a potential treatment of verapamil toxicity and reversal agent for anesthesia-induced neuromuscular blockade. To date, there have been limited reports of either intentional or accidental 4-AP toxicity in humans. Both a case of a patient with 4-AP toxicity and review of the literature are discussed, highlighting commonalities observed in overdose.
CASE REPORT: A 37-year-old man with progressive MS presented with diaphoresis, delirium, agitation, and choreathetoid movements after a presumed 4-AP overdose. 4-AP concentration at 6 h was 140 ng/mL. With aggressive benzodiazepine administration and intubation, he recovered uneventfully.
DISCUSSION: The commonalities associated with 4-AP toxicity conforms to what is known about its mechanism of action combining cholinergic features including diaphoresis, altered mental status, and seizures with dopamine-related movement abnormalities including tremor, choreoathetosis, and dystonia. Management of patients poisoned by 4-AP centers around good supportive care with definitive airway management and controlling CNS hyperexcitability aggressively with gamma-aminobutyric acid agonist agents. Adjunctive use of dopamine antagonists for extrapyramidal effects after sedation is a treatment possibility. As 4-aminopyridine recently received Federal Drug Administration approval for the treatment of ambulation in patients with MS, physicians should be keenly aware of its presentation, mechanism of action, and management in overdose
The Littlest Higgs
We present an economical theory of natural electroweak symmetry breaking,
generalizing an approach based on deconstruction. This theory is the smallest
extension of the Standard Model to date that stabilizes the electroweak scale
with a naturally light Higgs and weakly coupled new physics at TeV energies.
The Higgs is one of a set of pseudo Goldstone bosons in an
nonlinear sigma model. The symmetry breaking scale is around a TeV, with
the cutoff \Lambda \lsim 4\pi f \sim 10 TeV. A single electroweak doublet,
the ``little Higgs'', is automatically much lighter than the other pseudo
Goldstone bosons. The quartic self-coupling for the little Higgs is generated
by the gauge and Yukawa interactions with a natural size ,
while the top Yukawa coupling generates a negative mass squared triggering
electroweak symmetry breaking. Beneath the TeV scale the effective theory is
simply the minimal Standard Model. The new particle content at TeV energies
consists of one set of spin one bosons with the same quantum numbers as the
electroweak gauge bosons, an electroweak singlet quark with charge 2/3, and an
electroweak triplet scalar. One loop quadratically divergent corrections to the
Higgs mass are cancelled by interactions with these additional particles.Comment: 15 pages. References added. Corrected typos in the discussion of the
top Yukawa couplin
Eisenstein Series of Weight One, q-Averages of the 0-Logarithm and Periods of Elliptic Curves
For any elliptic curve E over k ⊂ R with E(C) = C^×/q^Z, q = e^(2πiz),Im(z) >, we study the q-average D_(0,q), defined on E(C), of the function D_0(z) = Im(z/(1−z)). Let Ω+(E) denote the real period of E. We show that there is a rational function R ∈ Q(X_1(N)) such that for any non-cuspidal real point s ∈ X_1(N) (which defines an elliptic curve E(s) over R together with a point P(s) of order N), πD_(0,q)(P(s)) equals Ω+(E(s))R(s). In particular, if s is Q-rational point of X_1(N), a rare occurrence according to Mazur, R(s) is a rational number
The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
We analyze the physical conditions of the cool, photoionized (T
K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density
measurements for 44 gaseous halos within 160 kpc of galaxies at . These data are well described by simple photoionization models, with
the gas highly ionized (n/n) by the
extragalactic ultraviolet background (EUVB). Scaling by estimates for the
virial radius, R, we show that the ionization state (tracked by the
dimensionless ionization parameter, U) increases with distance from the host
galaxy. The ionization parameters imply a decreasing volume density profile
n = (10)(R/R. Our derived
gas volume densities are several orders of magnitude lower than predictions
from standard two-phase models with a cool medium in pressure equilibrium with
a hot, coronal medium expected in virialized halos at this mass scale. Applying
the ionization corrections to the HI column densities, we estimate a lower
limit to the cool gas mass M
M for the volume within R R. Allowing for an
additional warm-hot, OVI-traced phase, the CGM accounts for at least half of
the baryons purported to be missing from dark matter halos at the 10
M scale.Comment: 19 pages, 12 Figures, and a 37-page Appendix with 36 additional
figures. Accepted to ApJ June 21 201
Electroweak Precision Constraints on the Littlest Higgs Model with T Parity
We compute the leading corrections to the properties of W and Z bosons
induced at the one-loop level in the SU(5)/SO(5) Littlest Higgs model with T
parity, and perform a global fit to precision electroweak data to determine the
constraints on the model parameters. We find that a large part of the model
parameter space is consistent with data. Values of the symmetry breaking scale
as low as 500 GeV are allowed, indicating that no significant fine tuning in
the Higgs potential is required. We identify a region within the allowed
parameter space in which the lightest T-odd particle, the partner of the
hypercharge gauge boson, has the correct relic abundance to play the role of
dark matter. In addition, we find that a consistent fit to data can be obtained
for large values of the Higgs mass, up to 800 GeV, due to the possibility of a
partial cancellation between the contributions to the T parameter from Higgs
loops and new physics.Comment: 23 pages, 9 figures. Minor correction
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