In this paper the authors report on a study of cloud and surface flux processes in the tropical eastern Pacific Ocean based on a series of ship-based cloud and flux measurements made during fall ...(1999–2002) and spring (2000–02) maintenance cruises along the 95° and 110°W Tropical Atmosphere Ocean (TAO) buoy lines between 8°S and 12°N. The year-to-year and seasonal variabilities of many of the meteorological and oceanic means are relatively small. However, notable seasonal variability is found in the northern branch of the intertropical convergence zone, the north–south sea surface temperature gradient, and heat fluxes north of the equator. In the fall, the strengthening of the north–south SST contrast enhances convective activity (more and deeper clouds, precipitation, southerly inflow) in the area around 6°N, 95°W; diurnal variations of low cloud fraction were weak. Spring cloud fraction varied significantly over the diurnal cycle with substantially lower cloud fraction during the day south of 5°N. Relatively low average cloud-base heights around the equator are due to chilling of the marine boundary layer over the cold tongue.
Cloud radiative forcing strongly correlates with cloud fraction; clouds in the observation region cool the surface by about 40 W m−2in both seasons. Cloud forcing estimates from the ship data, the TAO buoys, and International Satellite Cloud Climatology Project (ISCCP) products were combined to form a consensus observation dataset that is compared with the second NCEP reanalysis (NCEP-2) and 40-yr ECMWF Re-Analysis (ERA-40) cloud forcing values. The reanalysis products were within 10 W m−2of the observations for IR cloud forcing but substantially overestimated the solar cloud forcing, particularly in spring.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To evaluate the activity of posaconazole for treatment of zygomycosis, a disease for which therapeutic options are limited, we conducted a retrospective study including 91 patients with zygomycosis ...(proven zygomycosis, 69 patients; probable zygomycosis, 22 patients). Patients had infection that was refractory to prior antifungal treatment (n = 81) or were intolerant of such treatment (n = 10) and participated in the compassionate-use posaconazole (800 mg/day) program. The rate of success (i.e., either complete or partial response) at 12 weeks after treatment initiation was 60%, and 21% of patients had stable disease. The overall high success and survival rates reported here provide encouraging data regarding posaconazole as an alternative therapy for zygomycosis.
We sought to determine whether skeletal muscle oxidative capacity, fiber type proportions, and fiber size, capillary density or muscle mass might explain the impaired exercise tolerance in chronic ...heart failure (CHF). Previous studies are equivocal regarding the maladaptations that occur in the skeletal muscle of patients with CHF and their role in the observed exercise intolerance.
Total body O2 uptake (VO2peak) was determined in 14 CHF patients and 8 healthy sedentary similar-age controls. Muscle samples were analyzed for mitochondrial adenosine triphosphate (ATP) production rate (MAPR), oxidative and glycolytic enzyme activity, fiber size and type, and capillary density. CHF patients demonstrated a lower VO2peak (15.1±1.1 versus 28.1±2.3 mL·kg−1·min−1, P<.001) and capillary to fiber ratio (1.09±0.05 versus 1.40±0.04; P<.001) when compared with controls. However, there was no difference in capillary density (capillaries per square millimeter) across any of the fiber types. Measurements of MAPR and oxidative enzyme activity suggested no difference in muscle oxidative capacity between the groups.
Neither reductions in muscle oxidative capacity nor capillary density appear to be the cause of exercise limitation in this cohort of patients. Therefore, we hypothesize that the low VO2peak observed in CHF patients may be the result of fiber atrophy and possibly impaired activation of oxidative phosphorylation.
On the Evolution of the Fontan Operation Van Hare, George F., MD
Journal of the American College of Cardiology,
09/2010, Letnik:
56, Številka:
11
Journal Article
Atrial fibrillation (AF) is mediated by oxidative stress, neurohormonal activation, and inflammatory activation. Serum uric acid (SUA) is a surrogate marker of oxidative stress. Xanthine oxidase ...produces SUA and is upregulated by inflammation and neurohormones.
To perform a meta-analysis to evaluate the evidence supporting an association between AF and SUA.
We searched the MEDLINE database (1966 to 2013) supplemented by manual searches of bibliographies of key relevant articles. We selected all cross-sectional and cohort studies in which SUA was measured and AF was reported. In cross-sectional studies, we calculated the pooled standardized mean difference of SUA between those with AF and those without AF. In cohort studies, we calculated the pooled relative risk with the corresponding 95% confidence interval (CI) for incident AF by using the random effects method.
The search strategy yielded 40 studies, of which only 9 met our eligibility criteria. The 6 cross-sectional studies comprised 7930 evaluable patients with a median prevalence of heart failure of 4% (IQR 0%-100%). The standardized mean difference of SUA for those with AF was 0.42 (95% CI 0.27-0.58) compared with those without AF. The 3 cohort studies evaluated 138,306 individuals without AF. The relative risk of having AF for those with high SUA was 1.67 (95% CI 1.23-2.27) compared with those with normal SUA.
High SUA is associated with AF in both cross-sectional and cohort studies. It is unclear whether SUA represents a disease marker or a treatment target.
Abstract Atrioventricular node reentry tachycardia is an incompletely understood substrate for supraventricular tachycardia. Although there is agreement that the mechanism involves functionally ...separate fast and slow AV node pathways, which are somewhat anatomically discrete, the anatomical basis for the reentrant circuit is not well defined. Furthermore, the nature of the long fast pathway effective refractory period is not known but most likely involves electrotonic interactions between fast and slow AV nodal pathways. The proposition that the mechanism is related to features of cell coupling has been studied in a finite element computer model. Because the calculations rely on assumptions about nodal size and space constants, clinical studies in smaller and younger patients are naturally of interest.
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