653 research outputs found
Electromagnetic response of LaO_0.94F_0.06FeAs: AC susceptibility and microwave surface resistance
We discuss on the electromagnetic response of a polycrystalline sample of
LaO_0.94F_0.06FeAs exposed to DC magnetic fields up to 10 kOe. The low- and
high-frequency responses have been investigated by measuring the AC
susceptibility at 100 kHz and the microwave surface resistance at 9.6 GHz. At
low as well as high DC magnetic fields, the susceptibility strongly depends on
the amplitude of the AC driving field, highlighting enhanced nonlinear effects.
The field dependence of the AC susceptibility exhibits a magnetic hysteresis
that can be justified considering the intragrain-field-penetration effects on
the intergrain critical current density. The microwave surface resistance
exhibits a clockwise magnetic hysteresis, which cannot be justified in the
framework of the critical-state models of the Abrikosov-fluxon lattice; it may
have the same origin as that detected in the susceptibility.Comment: 8 pages, 4 embedded eps figures; Proceedings of the 9th EUCAS
Conference (Dresden, Germany, September 13-17, 2009
Gender and the systemic hypertension-snoring association: a questionnaire-based case-control study.
Since the role of gender in the association between hypertension and snoring is unknown, we studied it while accounting for age and body mass index (BMI) as confounding variables. A questionnaire on snoring was administered to 90 hypertensive (HT) subjects (45 men and 45 women) and to 90 normotensive (NT) subjects matched for gender, age and BMI. As expected, snoring was more commonly reported by men than by women, but no significant difference was found between HT and NT men, irrespective of age. Conversely, heavy snoring was more frequently reported by HT than NT women; habitual snoring was more common among young (age50 years) HT than NT women; and heavy snoring was more common among older (age50 years) HT than NT women. These data suggest an effect of gender on the hypertension-snoring association: in men, snoring may be accounted for by age and BMI whether or not hypertension is present, whereas in women the natural history of snoring appears different and more severe in HT than in NT. Although the mechanism(s) responsible for the differences between men and women are obscure at present, gender may be an important variable in the systemic hypertension-snoring association
Endurance training damages small airway epithelium in mice.
RATIONALE: In athletes, airway inflammatory cells were found to be increased in
induced sputum or bronchial biopsies. Most data were obtained after exposure to
cold and dry air at rest or during exercise. Whether training affects epithelial
and inflammatory cells in small airways is unknown.
OBJECTIVES: To test whether endurance training under standard environmental
conditions causes epithelial damage and inflammation in the small airways of
mice.
METHODS AND MEASUREMENTS: Formalin-fixed, paraffin-embedded lung sections were
obtained in sedentary (n = 14) and endurance-trained (n = 16) Swiss mice at
baseline and after 15, 30, and 45 days of training. The following variables were
assessed (morphometry and immunohistochemistry) in small airways (basement
membrane length < 1 mm): (1) integrity, proliferation, and apoptosis of
bronchiolar epithelium; and (2) infiltration, activation, and apoptosis of
inflammatory cells.
MAIN RESULTS: Compared with sedentary mice, bronchiolar epithelium of trained
mice showed progressive loss of ciliated cells, slightly increased thickness,
unchanged goblet cell number and appearance, and increased apoptosis and
proliferation (proliferating cell nuclear antigen) (p < 0.001 for all variables).
Leukocytes (CD45(+) cells) infiltrated airway walls (p < 0.0001) and accumulated
within the lumen (p < 0.001); however, apoptosis of CD45(+) cells did not differ
between trained and sedentary mice. Nuclear factor-kappaB translocation and
inhibitor-alpha of NF-kappaB (IkappaBalpha) phosphorylation were not increased in
trained compared with sedentary mice.
CONCLUSIONS: Bronchiolar epithelium showed damage and repair associated with
endurance training. Training increased inflammatory cells in small airways, but
inflammatory activation was not increased. These changes may represent an
adaptive response to increased ventilation during exercise
Riverfront Cities Report: A Strategy for Helping Protect the Mississippi's Environment.
A report to the McKnight Foundation from the Center for Urban and Regional Affairs, University of Minnesota. April 1992
European Union directive 2014/85/EU on driver licensing in obstructive sleep apnoea:early experiences with its application in the UK
OSA patients’ risk of RTA should be assessed using detailed driving history with specific focus on “red flags” http://ow.ly/mxPi305isn
Triclorosilane-mediated stereoselective synthesis of beta-amino esters and their conversion to highly enantiomerically enriched beta-lactams
A highly stereoselective trichlorosilane-mediated reduction of N-benzyl enamines was developed; the combination of a low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to perform the reaction on substrates with different structural features often with total control of the stereoselectivity. By easy deprotection through hydrogenolysis followed by conversion of \u3b2-aminoester to 2-azetidinones, the synthesis of enantiomerically pure \u3b2-lactams (>98% e.e.) was successfully accomplished
Sex differences in obstructive sleep apnoea
Obstructive sleep apnoea (OSA) and obstructive sleep apnoea/hypopnoea syndrome (OSAHS) have long been considered predominantly male-related conditions. The clinical presentation of sleep disordered breathing in females differs from males and can vary with age and physiological status, e.g. menopause and pregnancy. Overall, females appear to be more symptomatic, with lower apnoea–hypopnoea index scores compared to males. Furthermore, they appear to have more prolonged partial upper airway obstruction, and may report insomnia as a symptom of OSAHS more frequently. As a consequence of these differences in clinical presentation, females with sleep disordered breathing are often underdiagnosed and undertreated compared to males. This review is aimed at discussing the epidemiology, clinical presentation, pathophysiology and hormonal and metabolic differences in females who present with OSA/OSAHS in comparison to males
15 (S)-HETE modulates LTB4 production and neutrophil chemotaxis in chronic bronchitis
We evaluated the levels of 15(S)-hydroxyeicosatetraenoic acid [15(S)-HETE] and the expression of 15-lipoxygenase (15-LO) mRNA in induced sputum obtained from 10 control and 15 chronic bronchitis subjects. 15(S)-HETE was evaluated by reverse phase high-performance liquid chromatography separation followed by specific RIA. 15-LO mRNA expression was determined by primed in situ labeling. The levels of both soluble and cell-associated 15(S)-HETE resulted significantly higher in chronic bronchitis than in control subjects. The percentage of cells expressing 15-LO mRNA was significantly higher in chronic bronchitis than in control subjects (P < 0.01). Double staining for specific cell type markers and 15-LO mRNA showed macrophages and neutrophils positive for 15-LO, whereas similar staining of peripheral blood neutrophils did not show evidence for 15-LO expression, suggesting that expression of 15-LO in neutrophils takes place on migration into the airways. Because 15(S)-HETE inversely correlated with the percentage of neutrophils in sputum of chronic bronchitis subjects, we studied the effect of 15(S)-HETE on leukotriene B4 (LTB4) production in vitro and evaluated the concentration of LTB4 in induced sputum and the contribution of LTB4 to the chemotactic activity of induced sputum samples ex vivo. The results obtained indicate that macrophages and neutrophils present within the airways of chronic bronchitis subjects express 15-LO mRNA; increased basal levels of 15(S)-HETE may contribute to modulate, through the inhibition of 5-lipoxygenase metabolites production, neutrophil infiltration and airway inflammation associated with chronic bronchitis
- …