Although well-known for their thromboresistance, bileaflet mechanical heart valves (BMHV) require lifelong anti-thrombotic therapy. This must be associated with a certain level of thrombogenicity. ...Since both thromboresistance and thrombogenicity are explained by the blood-artificial surface or liquid-solid interactions, the aim of the present study was to explore BMHV thromboresistance from new perspectives. The wettability of BMHV pyrolytic carbon (PyC) occluders was investigated in under-liquid conditions. The submerged BMHV wettability clarifies the mechanisms involved in the thromboresistance.
The PyC occluders of a SJM Regent™ BMHV were previously laser irradiated, to create a surface hierarchical nano-texture, featuring three nano-configurations. Additionally, four PyC occluders of standard BMHV (Carbomedics, SJM Regent
, Bicarbon
, On-X
), were investigated. All occluders were evaluated in under-liquid configuration, with silicon oil used as the working droplet, while water, simulating blood, was used as the surrounding liquid. The under-liquid droplet-substrate wetting interactions were analyzed using contact angle goniometry.
All the standard occluders showed very low contact angle, reflecting a pronounced affinity for non-polar molecules. No receding of the contact line could be observed for the untreated occluders. The smallest static contact angle of around 61° could be observed for On-X
valve (the only valve made of full PyC). The laser-treated occluders strongly repelled oil in underwater conditions. A drastic change in their wetting behaviour was observed depending on the surrounding fluid, displaying a hydrophobic behaviour in the presence of air (as the surrounding medium), and showing instead a hydrophilic nature, when surrounded by water.
BMHV "fear" water and blood. The intrinsic affinity of BMHV for nonpolar fluids can be translated into a tendency to repel polar fluids, such as water and blood. The blood-artificial surface interaction in BMHV is minimized. The contact between blood and BMHV surface is drastically reduced by polar-nonpolar Van der Waals forces. The "hydro/bloodphobia" of BMHV is intrinsically related to their chemical composition and their surface energy, thus their material: PyC indeed. Pertaining to thromboresistance, the surface roughness does not play a significant role. Instead, the thromboresistance of BMHV lies in molecular interactions. BMHV wettability can be tuned by altering the surface interface, by means of nanotechnology.
Contained rupture of the ascending aorta is a rare condition, but the severity of this complication enforces strict guidelines for its prevention and a prompt diagnosis, once already occurred.
A ...66-year-old man with a history of type 2 diabetes, longstanding aortic valve stenosis and aortic root aneurysm of 47 mm was hospital admitted for elective surgery. A Bentall-De Bono procedure was performed in order to replace the stenotic bicuspid aortic valve and exclude the dilated portion of the aortic wall. Intraoperatively, a discontinuity of the aortic wall, just above the aortic annulus, at the non-coronary sinus of Valsalva was incidentally observed. The aortic wall discontinuity was none other than a contained aortic rupture. The preoperative CT-scan images were afterwards analyzed by the radiologist, in order to identify the contained aortic rupture. Indeed a false aneurysm of the non-coronary sinus of Valsalva of a maximum diameter of 15 mm was detected, thanks to a 3D reconstruction.
The diagnosis of contained aortic rupture is certainly demanding, particularly in absence of signs or symptoms of rupture in a chamber of the heart or in the pericardium. Although this case represents a consensus of experts' opinion, the recognition of these specific cases in which the risk of dissection, rupture or death is at its highest, would allow to operate at the appropriate time, improving the outcomes.
To determine whether temozolomide is an active agent in the treatment of children with high-grade astrocytomas and whether survival is influenced by the expression of the ...O6-methylguanine-methyltransferase gene (MGMT) in these patients. In the Children's Oncology Group study ACNS0126, 107 patients with a diagnosis of anaplastic astrocytoma (AA), glioblastoma multiforme (GBM), or gliosarcoma were enrolled. All patients underwent concomitant chemoradiotherapy with temozolomide, followed by adjuvant chemotherapy with temozolomide. The outcomes were compared with those of children treated in Children's Cancer Group (CCG) study CCG-945. Formalin-fixed, paraffin-embedded tumor tissue was available in 71 cases for immunohistochemical analysis of MGMT expression. Ninety patients were deemed eligible, 31 with AA, 55 with GBM, and 4 with other eligible diagnoses. The 3-year event-free survival (EFS) and overall survival (OS) rates were 11 ± 3% and 22 ± 5%, respectively. There was no evidence that temozolomide given during radiation therapy and as adjuvant therapy resulted in improved EFS compared with that found in CCG-945 (p = 0.98). The 3-year EFS rate for AA was 13 ± 6% in ACNS0126 compared with 22 ± 5.5% in CCG-945 (p = 0.95). The 3-year EFS rate for GBM was 7 ± 4% in ACNS0126 compared with 15 ± 5% in CCG-945 (p = 0.77). The 2-year EFS rate was 17 ± 5% among patients without MGMT overexpression and 5 ± 4% among those with MGMT overexpression (p = 0.045). Temozolomide failed to improve outcome in children with high-grade astrocytomas. MGMT overexpression was adversely associated with survival.
The objective of this randomized, double-blind, placebo-controlled study was to investigate the efficacy and safety of paroxetine in outpatients with generalized anxiety disorder (GAD).
Male and ...female outpatients 18 years and older who met DSM-IV criteria for GAD and had baseline scores of at least 20 on the Hamilton Rating Scale for Anxiety (HAM-A) were randomly assigned to treatment with paroxetine (20-50 mg/day) or placebo for 8 weeks. The primary efficacy variable was the mean change from baseline in the total score of the HAM-A. Additional key efficacy variables were the change from baseline in the scores of the HAM-A items anxious mood and tension, the anxiety subscale of the Hospital Anxiety and Depression Scale, and the Sheehan Disability Scale (SDS). The proportions of patients fulfilling response and remission criteria at week 8 were also determined.
The intent-to-treat population included 324 patients. At week 8, compared with the placebo group (N = 163), the paroxetine group (N = 161) had a significantly greater reduction of GAD symptoms on all of the above-mentioned efficacy variables. On the HAM-A anxious mood item, which encompasses the cardinal symptoms of GAD, significantly greater efficacy was observed from week 1 and on the SDS significantly greater improvement was documented in the domain "social life" as early as week 4 for paroxetine compared with placebo. In both the last-observation-carried-forward and completer data sets, significantly greater proportions of paroxetine-treated patients achieved response or remission by week 8. Treatment with paroxetine was well tolerated, and the number and type of adverse events recorded in the paroxetine group correspond to the known safety profile of this medication.
Paroxetine in doses of 20 to 50 mg once daily is effective in the treatment of patients with GAD. Improvement of core symptoms of GAD occurs early and is associated with significant reduction in disability after only 8 weeks of treatment.
"Iraq is rapidly descending into all-out civil war. Unfortunately, the United States probably will not be able to just walk away from the chaos. Even setting aside the humanitarian nightmare that ...will ensue, a full-scale civil war would likely consume more than Iraq: historically, such massive conflicts have often had highly deleterious effects on neighboring countries and other outside states. Spillover from an Iraq civil war could be disastrous." Thus begins this sobering analysis of what the near future of Iraq could look like, and what America can do to reduce the threat of wider conflict. Preventing spillover of the Iraqi conflict into neighboring states must be a top priority. In explaining how that can be accomplished, Daniel Byman and Kenneth Pollack draw on their own considerable expertise as well as relevant precedents. The authors scrutinize several recent civil wars, including Lebanon, Chechnya, Afghanistan, Kosovo, and Bosnia. After synthesizing those experiences into lessons on how civil wars affect other nations, Byman and Pollack draw from them to produce recommendations for U.S. policy. Even while the Bush Administration attempts to prevent further deterioration of the situation in Iraq, it needs to be planning how to deal with a full-scale civil war if one develops.
This article analyzes the roles & impact of individual personalities in international relations. The article discusses how a state or region may be affected by the influence of one leader & what ...conditions present the greatest influence of an individual. The article dismisses the theories of political scientists who argue that one individual does not have the power to influence the history of the nation or world. The article discusses five historical situations that are seen in hindsight as resting on the existence & actions of a single individual. E. Miller
Abstract
OBJECTIVES
The liquid–solid interactions have attracted broad interest since solid surfaces can either repel or attract fluids, configuring a wide spectrum of wetting states (from ...superhydrophilicity to superhydrophobicity). Since the blood–artificial surface interaction of bileaflet mechanical heart valves essentially represents a liquid–solid interaction, we analysed the thrombogenicity of mechanical heart valve prostheses from innovative perspectives. The aim of the present study was to modify the surface wettability of standard St. Jude Medical Regent™ occluders.
METHODS
Four pyrolytic carbon occluders were irradiated by means of ultra-short pulse laser, to create 4 different nanotextures (A–D), the essential prerequisite to achieve superhydrophobicity. The static surface wettability of the occluders was qualified by the contact angle (θ) of 2 µl of purified water, using the sessile drop technique. The angle formed between the liquid–solid and the liquid–vapour interface was the contact angle and was obtained by analysing the droplet images captured by a camera. The morphology of the occluders was characterized and analysed by a scanning electron microscope at different magnifications.
RESULTS
The scanning electron microscope analysis of the textures revealed 2 different configurations of the pillars since A and B showed well-rounded shaped tops and C and D flat tops. The measured highest contact angles were comprised between 108.1° and 112.7°, reflecting an improved hydrophobicity of the occluders. All the textures exhibited, to different extents, an orientation (horizontal or vertical), which was strictly related to the observed anisotropy.
CONCLUSIONS
In this very early phase of our research, we were able to demonstrate that the intrinsic wettability of pyrolytic carbon occluders can be permanently modified, increasing the water repellency.
Valvular heart diseases represents a major public-health problem and a burden of the upcoming years 1.
Crafting a new policy toward Iran is a complicated, uncertain, and perilous challenge. Since it is an extremely complex society, with an opaque political system, it is no wonder that the United ...States has not yet figured out the puzzle that is Iran. With the clock ticking on Iran's pursuit of nuclear capabilities, solving this puzzle is more urgent than ever. In Which Path to Persia? a group of experts with the Saban Center for Middle East Policy at Brookings lays out the courses of action available to the United States. What are the benefits and drawbacks of airstrikes? Can engagement be successful? Is regime change possible? In answering such questions, the authors do not argue for one approach over another. Instead, they present the details of the policies so that readers can understand the complexity of the challenge and decide for themselves which course the United States should take.
Abstract
Background
To provide a standardized, risk-adjusted method for summarizing antibiotic use (AU), enable hospitals to track their AU over time and compare their AU data to national benchmarks, ...the Centers for Disease Control and Prevention developed the Standardized Antimicrobial Administration Ratio (SAAR).
Methods
Hospitals reporting to the National Healthcare Safety Network (NHSN) AU Option collect and submit aggregated AU data electronically as antimicrobial days of therapy per patient days present. SAARs were developed for specific NHSN adult and pediatric patient care locations and cover five antimicrobial agent categories: (1) broad-spectrum agents predominantly used for hospital-onset/multi-drug resistant bacteria; (2) broad-spectrum agents predominantly used for community-acquired infections; (3) anti-methicillin-resistant Staphylococcus aureus agents; (4) agents predominantly used for surgical site infection prophylaxis; and (5) all antibiotic agents. The SAAR is an observed-to-predicted use ratio where predicted use is estimated from a statistical model; a SAAR of 1 indicates that observed use and predicted use are equal.
Results
Most location-level SAARs were statistically significantly different than 1: adult locations up to 52% lower than 1 and up to 41% higher than 1. Median SAARs in adult and pediatric ICUs had a range of 0.667-1.119. SAAR distributions serve as an external comparison to national SAARs.
Conclusions
This is the first aggregate AU metric that uses point-of-care, antimicrobial administration data electronically reported to a national surveillance system to enable risk-adjusted, AU comparisons across multiple hospitals. Endorsed by the National Quality Forum, SAARs provide AU benchmarks that stewardship programs can use to help drive improvements.
The Centers for Disease Control and Prevention has developed a new metric, the standardized antimicrobial administration ratio, that uses point-of-care, antimicrobial administration data electronically reported to a national surveillance system, to enable risk-adjusted, antibiotic use comparisons across multiple hospitals and health systems.
Ozone pollution in the Southeast US involves complex chemistry driven by emissions of anthropogenic nitrogen oxide radicals (NO(x) triple bond NO + NO2) and biogenic isoprene. Model estimates of ...surface ozone concentrations tend to be biased high in the region and this is of concern for designing effective emission control strategies to meet air quality standards. We use detailed chemical observations from the SEAC(exp 4)RS aircraft campaign in August and September 2013, interpreted with the GEOS-Chem chemical transport model at 0.25 deg x 0.3125 deg horizontal resolution, to better understand the factors controlling surface ozone in the Southeast US. We find that the National Emission Inventory (NEI) for NO(x) from the US Environmental Protection Agency (EPA) is too high. This finding is based on SEAC(exp 4)RS observations of NO(x) and its oxidation products, surface network observations of nitrate wet deposition fluxes, and OMI satellite observations of tropospheric NO2 columns. Our results indicate that NEI NO(x) emissions from mobile and industrial sources must be reduced by 30-60%, dependent on the assumption of the contribution by soil NO(x) emissions. Upper-tropospheric NO2 from lightning makes a large contribution to satellite observations of tropospheric NO2 that must be accounted for when using these data to estimate surface NO(x) emissions. We find that only half of isoprene oxidation proceeds by the high-NO(x) pathway to produce ozone; this fraction is only moderately sensitive to changes in NO(x) emissions because isoprene and NO(x) emissions are spatially segregated. GEOS-Chem with reduced NO(x) emissions provides an unbiased simulation of ozone observations from the aircraft and reproduces the observed ozone production efficiency in the boundary layer as derived from a regression of ozone and NO(x) oxidation products. However, the model is still biased high by 6 plus or minus 14 ppb relative to observed surface ozone in the Southeast US. Ozonesondes launched during midday hours show a 7 ppb ozone decrease from 1.5 km to the surface that GEOS-Chem does not capture. This bias may reflect a combination of excessive vertical mixing and net ozone production in the model boundary layer.
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