Basal cusp enlargement for repair of aortic valve insufficiency

ObjectiveThe aim of this study was to evaluate the clinical and echocardiographic results after aortic valve reconstruction with a novel surgical technique consisting of basal cusp enlargement with an autologous pericardial patch.MethodsBetween December 2005 and June 2008, a total of 106 consecutive patients underwent elective valve-sparing aortic root repair at Cardiovascular Clinic, Bad Neustadt, Germany. Fifty-nine patients required additional procedures on the aortic cusps; among them, in 10 cases basal cusp enlargement was used for restoration of coaptation area. All these patients had an ascending aortic aneurysm combined with aortic insufficiency, which was severe (4+) in 2 cases and moderate to severe (3+) in 4. The root repair was performed with valve reimplantation (David technique) in 1 case and the author's own single-patch technique in the other 9. Partial and total arch replacements were performed in 3 and 1 cases, respectively.ResultsThe postoperative echocardiography at discharge showed no aortic regurgitation in 7 cases and trivial regurgitation in 3. The average coaptation height of the leaflets was 9.9 ± 0.6 mm, and the mean gradient across the valve was 5.4 ± 1.9 mm Hg. At follow-up as late as 31 months, all patients were alive with echocardiographic findings unchanged from the early postoperative examinations.ConclusionsThe technique presented here allows an individualized reconstruction of the aortic cusps, leading to considerable improvement in coaptation area, in patients who have aortic leaflet prolapse or restriction caused by complex aortic root and valve disease

Poisson-Jacobi reduction of homogeneous tensors

The notion of homogeneous tensors is discussed. We show that there is a one-to-one correspondence between multivector fields on a manifold $M$, homogeneous with respect to a vector field $\Delta$ on $M$, and first-order polydifferential operators on a closed submanifold $N$ of codimension 1 such that $\Delta$ is transversal to $N$. This correspondence relates the Schouten-Nijenhuis bracket of multivector fields on $M$ to the Schouten-Jacobi bracket of first-order polydifferential operators on $N$ and generalizes the Poissonization of Jacobi manifolds. Actually, it can be viewed as a super-Poissonization. This procedure of passing from a homogeneous multivector field to a first-order polydifferential operator can be also understood as a sort of reduction; in the standard case -- a half of a Poisson reduction. A dual version of the above correspondence yields in particular the correspondence between $\Delta$-homogeneous symplectic structures on $M$ and contact structures on $N$.Comment: 19 pages, minor corrections, final version to appear in J. Phys. A: Math. Ge

Traitement du PTI et de l’AHAI au cours du DICV : revue systématique de la littérature

INTRODUCTION: Ten to 15% of common variable immunodeficiencies (CVID) develop auto-immune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Treatment is based on immunosuppressants, which produce blocking effects in the CVID. Our objective was to assess their risk-benefit ratio in these immunocompromised patients. METHODS: We identified 17 articles detailing the treatment of AIHA and/or ITP in patients suffering from CVID through a systematic review of the MEDLINE database. RESULTS: The increased infectious risk with corticosteroids does not call into question their place in the first line of treatment of ITP and AIHA in CVID. High-doses immunoglobulin therapy remain reserved for ITP with a high risk of bleeding. In second-line treatment, rituximab appears to be effective, with a lower infectious risk than the splenectomy. Immunosuppressants (azathioprine, methotrexate, mycophenolate, cyclophosphamide, vincristine, ciclosporine) are moderately effective and often lead to severe infections, meaning that their use is justified only in resistant cases and steroid-sparing. Dapsone, danazol and anti-D immunoglobulins have an unfavorable risk-benefit ratio. The place of TPO receptor agonists is still to be defined. The establishment of immunoglobulin replacement in the place of immunosuppressants (except for short-term corticotherapy) or splenectomy appears to be essential to limit the risk of infections, including in the absence of previous infections. CONCLUSION: The presence of CVID does not mean that it is necessary to give up on corticosteroids as a first-line treatment and rituximab as a second-line treatment for AIHA and ITP, but it should be in addition to immunoglobulin replacement. A splenectomy should be reserved as a third-line treatment

Incorporating a canopy parameterization within a coupled fire-atmosphere model to improve a smoke simulation for a prescribed burn

Forecasting fire growth, plume rise and smoke impacts on air quality remains a challenging task. Wildland fires dynamically interact with the atmosphere, which can impact fire behavior, plume rises, and smoke dispersion. For understory fires, the fire propagation is driven by winds attenuated by the forest canopy. However, most numerical weather prediction models providing meteorological forcing for fire models are unable to resolve canopy winds. In this study, an improved canopy model parameterization was implemented within a coupled fire-atmosphere model (WRF-SFIRE) to simulate a prescribed burn within a forested plot. Simulations with and without a canopy wind model were generated to determine the sensitivity of fire growth, plume rise, and smoke dispersion to canopy effects on near-surface wind flow. Results presented here found strong linkages between the simulated fire rate of spread, heat release and smoke plume evolution. The standard WRF-SFIRE configuration, which uses a logarithmic interpolation to estimate sub-canopy winds, overestimated wind speeds (by a factor 2), fire growth rates and plume rise heights. WRF-SFIRE simulations that implemented a canopy model based on a non-dimensional wind profile, saw significant improvements in sub-canopy winds, fire growth rates and smoke dispersion when evaluated with observations

The association of histological and radiological indicators of breast cancer risk.

Previous work has shown that extensive mammographic dysplasia in women aged less than 50 was strongly associated with breast cancer but that the radiological appearance of ductal prominence was not associated with risk. In the present paper we examine the association between these mammographic signs in the breast and histological patterns in the terminal ductal lobular unit (TDLU), the region of the breast where breast cancer is believed to originate. Surgical biopsies from a consecutive series of women aged less than 50 were reviewed and classified according to the histopathology of the epithelium in the TDLU. Mammograms from the same subjects were independently classified according to the extent of the radiological signs of dysplasia and ductal prominence. Degree of histopathology and the extent of mammographic dysplasia were associated and atypia of the ductal type was found more frequently in patients with extensive dysplasia. However, the strength and statistical significance of the association varied according to the radiologist who classified the mammograms. No association was found between degree of histopathology and ductal prominence. These results add to the evidence that extensive mammographic dysplasia in women aged less than 50 is a risk factor for breast cancer. They do not indicate that the radiological signs of dysplasia are caused by histological changes in the TDLU

Evolution of trace gases and particles emitted by a chaparral fire in California

Biomass burning (BB) is a major global source of trace gases and particles. Accurately representing the production and evolution of these emissions is an important goal for atmospheric chemical transport models. We measured a suite of gases and aerosols emitted from an 81 hectare prescribed fire in chaparral fuels on the central coast of California, US on 17 November 2009. We also measured physical and chemical changes that occurred in the isolated downwind plume in the first ~4 h after emission. The measurements were carried out onboard a Twin Otter aircraft outfitted with an airborne Fourier transform infrared spectrometer (AFTIR), aerosol mass spectrometer (AMS), single particle soot photometer (SP2), nephelometer, LiCor CO_2 analyzer, a chemiluminescence ozone instrument, and a wing-mounted meteorological probe. Our measurements included: CO_2; CO; NO_x; NH_3; non-methane organic compounds; organic aerosol (OA); inorganic aerosol (nitrate, ammonium, sulfate, and chloride); aerosol light scattering; refractory black carbon (rBC); and ambient temperature, relative humidity, barometric pressure, and three-dimensional wind velocity. The molar ratio of excess O_3 to excess CO in the plume (ΔO_3/ΔCO) increased from −5.13 (±1.13) × 10^(−3) to 10.2 (±2.16) × 10^(−2) in ~4.5 h following smoke emission. Excess acetic and formic acid (normalized to excess CO) increased by factors of 1.73 ± 0.43 and 7.34 ± 3.03 (respectively) over the same time since emission. Based on the rapid decay of C_2H_4 we infer an in-plume average OH concentration of 5.27 (±0.97) × 10^6 molec cm^(−3), consistent with previous studies showing elevated OH concentrations in biomass burning plumes. Ammonium, nitrate, and sulfate all increased over the course of 4 h. The observed ammonium increase was a factor of 3.90 ± 2.93 in about 4 h, but accounted for just ~36% of the gaseous ammonia lost on a molar basis. Some of the gas phase NH_3 loss may have been due to condensation on, or formation of, particles below the AMS detection range. NO_x was converted to PAN and particle nitrate with PAN production being about two times greater than production of observable nitrate in the first ~4 h following emission. The excess aerosol light scattering in the plume (normalized to excess CO_2) increased by a factor of 2.50 ± 0.74 over 4 h. The increase in light scattering was similar to that observed in an earlier study of a biomass burning plume in Mexico where significant secondary formation of OA closely tracked the increase in scattering. In the California plume, however, ΔOA/ΔCO_2 decreased sharply for the first hour and then increased slowly with a net decrease of ~20% over 4 h. The fraction of thickly coated rBC particles increased up to ~85% over the 4 h aging period. Decreasing OA accompanied by increased scattering/particle coating in initial aging may be due to a combination of particle coagulation and evaporation processes. Recondensation of species initially evaporated from the particles may have contributed to the subsequent slow rise in OA. We compare our results to observations from other plume aging studies and suggest that differences in environmental factors such as smoke concentration, oxidant concentration, actinic flux, and RH contribute significantly to the variation in plume evolution observations

Observations and analysis of organic aerosol evolution in some prescribed fire smoke plumes

Open biomass burning is a significant source of primary air pollutants such as particulate matter and non-methane organic gases. However, the physical and chemical atmospheric processing of these emissions during transport is poorly understood. Atmospheric 5 transformations of biomass burning emissions have been investigated in environmental chambers, but there have been limited opportunities to investigate these transformations in the atmosphere. In this study, we deployed a suite of real-time instrumentation on a Twin Otter aircraft to sample smoke from prescribed fires in South Carolina, conducting measurements at both the source and downwind to character10 ize smoke evolution with atmospheric aging. Organic aerosol (OA) within the smoke plumes was quantified using an Aerosol Mass Spectrometer (AMS), along with refractory black carbon (rBC) using a Single Particle Soot Photometer and carbon monoxide (CO) and carbon dioxide (CO2) using a Cavity Ring-Down Spectrometer. During the two fires for which we were able to obtain aerosol aging data, normalized excess mix15 ing ratios and “export factors” of conserved species (rBC, CO, CO2) were unchanged with increasing sample age. Investigation of AMS mass fragments indicated that the inplume fractional contribution (fm/z) to OA of the primary fragment (m/z 60) decreased downwind, while the fractional contribution of the secondary fragment (m/z 44) increased. Increases in f44 are typically interpreted as indicating chemical production 20 of secondary OA (SOA). Likewise, we observed an increase in the O:C elemental ratio downwind, which is usually associated with aerosol aging. However, the rapid mixing of these plumes into the background air suggests that these chemical transformations may be attributable to the dierent volatilities of the compounds that fragment to these m/z in the AMS. The gas-particle partitioning behavior of the bulk OA ob25 served during the study was consistent with the predictions from a parameterization developed for open biomass burning emissions in the laboratory. Furthermore, we observed no statistically-significant increase in total organic mass with atmospheric transport. Hence, our results suggest that dilution-driven evaporation likely dominated over chemical production of SOA within our smoke plumes, likely due to the fast dilution and limited aging times