179 research outputs found

    Phase partition of gaseous hexane and surface hydrophobicity of Fusarium solani when grown in liquid and solid media with hexanol and hexane

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    The filamentous fungus, Fusarium solani, was grown in liquid and solid culture with glucose, glycerol, 1-hexanol and n-hexane. The partition coefficient with gaseous hexane (HPC) in the biomass was lower when grown in liquid medium with 1-hexanol (0.4) than with glycerol (0.8) or glucose (1) The HPC for surface growth were 0.2 for 1-hexanol, 0.5 for glycerol, 0.6 for glucose, and 0.2 for F. solani biomass obtained from a biofilter fed with gaseous n-hexane. These values show a 200-fold increase in n-hexane solubility when compared to water (HPC = 42). Lower HPC values can be partially explained by increased lipid accumulation with 1-hexanol, 10.5% (w/w) than with glycerol (8.5% w/w) or glucose (7.1% w/w). The diameter of the hyphae diminished from 3 μm to 2 μm when F. solani was grown on solid media with gaseous n-hexane thereby doubling the surface area for gaseous substrate exchange. The surface hydrophobicity of the mycelia increased consistently with more hydrophobic substrates and the contact angle of a drop of water on the mycelial mat was 113° when grown on n-hexane as compared to 75° with glucose. The fungus thus adapts to hydrophobic conditions and these changes may explain the higher uptake of gaseous hydrophobic substances by fungi in biofilters

    Milieu- en habitatpreferenties van Nederlandse zoetwatermacrofauna

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    Macrofauna speelt een belangrijke rol in het beoordelen van de ecologische kwaliteit van oppervlaktewateren, bijvoorbeeld voor de Europese Kaderrichtlijn Water. Daarnaast kan de samenstelling van de macrofauna informatie geven over kenmerken van of problemen met een water (diagnostische waarde). Na een rapport waarin van een groot aantal Nederlandse soorten de zeldzaamheid is aangegeven (Nijboer & Verdonschot red. 2001), was het achterhalen van de milieu- en habitateisen van de macrofaunasoorten een logisch vervolg. Deze milieu- en habitatkennis maakt het mogelijk om gegevens over macrofauna te gebruiken om de toestand van het oppervlaktewater te omschrijven. Dit biedt een belangrijke meerwaarde bij het gebruik van bestaande biologische parameters in het water- en natuurbeheer

    Record RF performance of standard 90 nm CMOS technology

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    We have optimized 3 key RF devices realized in standard logic 90 nm CMOS technology and report a record performance in terms of n-MOS maximum oscillation frequency f/sub max/ (280 GHz), varactor tuning range and varactor and inductor quality factor

    The endothelial glycocalyx prefers albumin for evoking shear stress-induced, nitric oxide-mediated coronary dilatation

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    Background: Shear stress induces coronary dilatation via production of nitric oxide ( NO). This should involve the endothelial glycocalyx ( EG). A greater effect was expected of albumin versus hydroxyethyl starch ( HES) perfusion, because albumin seals coronary leaks more effectively than HES in an EG-dependent way. Methods: Isolated hearts ( guinea pigs) were perfused at constant pressure with Krebs-Henseleit buffer augmented with 1/3 volume 5% human albumin or 6% HES ( 200/0.5 or 450/0.7). Coronary flow was also determined after EG digestion ( heparinase) and with nitro-L-arginine ( NO-L-Ag). Results: Coronary flow ( 9.50 +/- 1.09, 5.10 +/- 0.49, 4.87 +/- 1.19 and 4.15 +/- 0.09 ml/ min/ g for `albumin', `HES 200', `HES 450' and `control', respectively, n = 5-6) did not correlate with perfusate viscosity ( 0.83, 1.02, 1.24 and 0.77 cP, respectively). NO-L-Ag and heparinase diminished dilatation by albumin, but not additively. Alone NO-L-Ag suppressed coronary flow during infusion of HES 450. Electron microscopy revealed a coronary EG of 300 nm, reduced to 20 nm after heparinase. Cultured endothelial cells possessed an EG of 20 nm to begin with. Conclusions: Albumin induces greater endothelial shear stress than HES, despite lower viscosity, provided the EG contains negative groups. HES 450 causes some NO-mediated dilatation via even a rudimentary EG. Cultured endothelial cells express only a rudimentary glycocalyx, limiting their usefulness as a model system. Copyright (c) 2007 S. Karger AG, Basel

    The effect of on-line position correction on the dose distribution in focal radiotherapy for bladder cancer

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to determine the dosimetric effect of on-line position correction for bladder tumor irradiation and to find methods to predict and handle this effect.</p> <p>Methods</p> <p>For 25 patients with unifocal bladder cancer intensity modulated radiotherapy (IMRT) with 5 beams was planned. The requirement for each plan was that 99% of the target volume received 95% of the prescribed dose. Tumor displacements from -2.0 cm to 2.0 cm in each dimension were simulated, using 0.5 cm increments, resulting in 729 simulations per patient. We assumed that on-line correction for the tumor was applied perfectly. We determined the correlation between the change in D<sub>99% </sub>and the change in path length, which is defined here as the distance from the skin to the isocenter for each beam. In addition the margin needed to avoid underdosage was determined and the probability that an underdosage occurs in a real treatment was calculated.</p> <p>Results</p> <p>Adjustments for tumor displacement with perfect on-line position correction resulted in an altered dose distribution. The altered fraction dose to the target varied from 91.9% to 100.4% of the prescribed dose. The mean D<sub>99% </sub>(± SD) was 95.8% ± 1.0%. There was a modest linear correlation between the difference in D<sub>99% </sub>and the change in path length of the beams after correction (R<sup>2 </sup>= 0.590). The median probability that a systematic underdosage occurs in a real treatment was 0.23% (range: 0 - 24.5%). A margin of 2 mm reduced that probability to < 0.001% in all patients.</p> <p>Conclusion</p> <p>On-line position correction does result in an altered target coverage, due to changes in average path length after position correction. An extra margin can be added to prevent underdosage.</p

    Treatment Duration of Febrile Urinary Tract Infections

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    Although febrile urinary tract infections (UTIs) are relatively common in adults, data on optimal treatment duration are limited. Randomized controlled trials specifically addressing the elderly and patients with comorbidities have not been performed. This review highlights current available evidence. Premenopausal, non-pregnant women without comorbidities can be treated with a 5–7 day regimen of fluoroquinolones in countries with low levels of fluoroquinolone resistance, or, if proven susceptible, with 14 days of trimethoprim-sulfamethoxazole. Oral β-lactams are less effective compared with fluoroquinolones and trimethoprim-sulfamethoxazole. In men with mild to moderate febrile UTI, a 2-week regimen of an oral fluoroquinolone is likely sufficient. Although data are limited, this possibly holds even in the elderly patients with comorbidities or bacteremia

    Pregnancy related anxiety and general anxious or depressed mood and the choice for birth setting:A secondary data-analysis of the DELIVER study

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    BACKGROUND: In several developed countries women with a low risk of complications during pregnancy and childbirth can make choices regarding place of birth. In the Netherlands, these women receive midwife-led care and can choose between a home or hospital birth. The declining rate of midwife-led home births alongside the recent debate on safety of home births in the Netherlands, however, suggest an association of choice of birth place with psychological factors related to safety and risk perception. In this study associations of pregnancy related anxiety and general anxious or depressed mood with (changes in) planned place of birth were explored in low risk women in midwife-led care until the start of labour. METHODS: Data (n = 2854 low risk women in midwife-led care at the onset of labour) were selected from the prospective multicenter DELIVER study. Women completed the Pregnancy Related Anxiety Questionnaire-Revised (PRAQ-R) to assess pregnancy related anxiety and the EuroQol-6D (EQ-6D) for an anxious and/or depressed mood. RESULTS: A high PRAQ-R score was associated with planned hospital birth in nulliparous (aOR 1.92; 95% CI 1.32–2.81) and parous women (aOR 2.08; 95% CI 1.55–2.80). An anxious or depressed mood was associated with planned hospital birth (aOR 1.58; 95% CI 1.20–2.08) and with being undecided (aOR 1.99; 95% CI 1.23–2.99) in parous women only. The majority of women did not change their planned place of birth. Changing from an initially planned home birth to a hospital birth later in pregnancy was, however, associated with becoming anxious or depressed after 35 weeks gestation in nulliparous women (aOR 4.17; 95% CI 1.35–12.89) and with pregnancy related anxiety at 20 weeks gestation in parous women (aOR 3.91; 95% CI 1.32–11.61). CONCLUSION: Low risk women who planned hospital birth (or who were undecided) more often reported pregnancy related anxiety or an anxious or depressed mood. Women who changed from home to hospital birth during pregnancy more often reported pregnancy related anxiety or an anxious or depressed mood in late pregnancy. Anxiety should be adequately addressed in the process of informed decision-making regarding planned place of birth in low risk women

    Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins

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    <p>Abstract</p> <p>Purpose</p> <p>The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM).</p> <p>Methods and materials</p> <p>Alignment data of 148 patients treated with inversed planned intensity modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT) of the head and neck (n = 31), chest (n = 72), abdomen (n = 15), and pelvis (n = 30) were evaluated. The patient set-up accuracy was assessed using orthogonal megavoltage electronic portal images of 2328 fractions of 173 planning target volumes (PTV). In 25 patients, two PTVs were analyzed where the PTVs were located in different anatomical sites and treated in two different radiotherapy courses. The patient set-up error and the corresponding SM were retrospectively determined assuming no online verification, online verification once a week and online verification every other day.</p> <p>Results</p> <p>The SM could be effectively reduced with increasing frequency of online verifications. However, a significant frequency of relevant set-up errors remained even after online verification every other day. For example, residual set-up errors larger than 5 mm were observed on average in 18% to 27% of all fractions of patients treated in the chest, abdomen and pelvis, and in 10% of fractions of patients treated in the head and neck after online verification every other day.</p> <p>Conclusion</p> <p>In patients where high set-up accuracy is desired, daily online verification is highly recommended.</p
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