149 research outputs found
Examination of the role of Mycoplasma bovis in bovine pneumonia and a mathematical model for its evaluation
The authors screened 34 large cattle herds for the presence of Mycoplasma bovis infection by examining slaughtered cattle for macroscopic lung lesions, by culturing M. bovis from lung lesions and at the same time by testing sera for the presence of antibodies against M. bovis. Among the 595 cattle examined, 33.9% had pneumonic lesions, mycoplasmas were isolated from 59.9% of pneumonic lung samples, and 10.9% of sera from those animals contained antibodies to M.bovis. In 25.2% of the cases M. bovis was isolated from lungs with no macroscopic lesions. The proportion of seropositive herds was 64.7%. The average seropositivity rate of individuals was 11.3% but in certain herds it exceeded 50%. A probability model was developed for examining the relationship among the occurrence
of pneumonia, the isolation of M. bovis from the lungs and the presence of M. bovis specific antibodies in sera
Implementation of a mobile 0.15-T intraoperative MR system in pediatric neuro-oncological surgery: feasibility and correlation with early postoperative high-field strength MRI
INTRODUCTION: We analyze our preliminary experience using the PoleStar N20 mobile intraoperative MR (iMR) system as an adjunct for pediatric brain tumor resection. METHODS: We analyzed 11 resections in nine children between 1Â month and 17Â years old. After resection, we acquired iMR scans to detect residual tumor and update neuronavigation. We compared final iMR interpretation by the neurosurgeon with early postoperative MR interpretation by a neuroradiologist. RESULTS: Patient positioning was straightforward, and image quality (T1 7-min 4-mm sequences) sufficient in all cases. In five cases, contrast enhancement suspect for residual tumor was noted on initial postresection iMR images. In one case, a slight discrepancy with postoperative imaging after 3Â months was no longer visible after 1Â year. No serious perioperative adverse events related to the PoleStar N20 were encountered, except for transient shoulder pain in two. CONCLUSIONS: Using the PoleStar N20 iMR system is technically feasible and safe for both supra- and infratentorial tumor resections in children of all ages. Their small head and shoulders favor positioning in the magnet bore and allow the field of view to cover more than the area of primary interest, e.g., the ventricles in an infratentorial case. Standard surgical equipment may be used without significant limitations. In this series, the use of iMR leads to an increased extent of tumor resection in 45Â % of cases. Correlation between iMR and early postoperative MR is excellent, provided image quality is optimal and interpretation is carefully done by someone sufficiently familiar with the system
Intraoperative magnetic resonance imaging versus standard neuronavigation for the neurosurgical treatment of glioblastoma: A randomized controlled trial.
BACKGROUND: Although the added value of increasing extent of glioblastoma resection
is still debated, multiple technologies can assist neurosurgeons in attempting to
achieve this goal. Intraoperative magnetic resonance imaging (iMRI) might be helpful
in this context, but to date only one randomized trial exists. METHODS: We included
14 adults with a supratentorial tumor suspect for glioblastoma and an indication for
gross total resection in this randomized controlled trial of which the interim
analysis is presented here. Participants were assigned to either ultra-low-field
strength iMRI-guided surgery (0.15 Tesla) or to conventional neuronavigation-guided
surgery (cNN). Primary endpoint was residual tumor volume (RTV) percentage.
Secondary endpoints were clinical performance, health-related quality of life
(HRQOL) and survival. RESULTS: Median RTV in the cNN group is 6.5% with an
interquartile range of 2.5-14.75%. Median RTV in the iMRI group is 13% with an
interquartile range of 3.75-27.75%. A Mann-Whitney test showed no statistically
significant difference between these groups (P =0.28). Median survival in the cNN
group is 472 days, with an interquartile range of 244-619 days. Median survival in
the iMRI group is 396 days, with an interquartile range of 191-599 days (P =0.81).
Clinical performance did not differ either. For HRQOL only descriptive statistics
were applied due to a limited sample size. CONCLUSION: This interim analysis of a
randomized trial on iMRI-guided glioblastoma resection compared with cNN-guided
glioblastoma resection does not show an advantage with respect to extent of
resection, clinical performance, and survival for the iMRI group. Ultra-low-field
strength iMRI does not seem to be cost-effective compared with cNN, although the
lack of a valid endpoint for neurosurgical studies evaluating extent of glioblastoma
resection is a limitation of our study and previous volumetry-based studies on this
topic.Peer reviewe
Governance Conditions for Improving Quality Drinking Water Resources: the Need for Enhancing Connectivity
Realising the water quality objectives of the European Water Framework Directive have appeared to stagnate over the last decade all across Europe because of their highly complex nature. In the literature, interactive governance approaches tend to be regarded as the best way of dealing with complex water issues, but so far little empirical evidence has been reported on this perspective in regard to water quality issues. In this paper we have analysed how conditions of governance contribute to the realisation of water quality objectives at different types of drinking water resources in the Netherlands. The analysis demonstrates the importance of addressing different hydrological scales, institutional levels and sectors and thus enhance connectivity in order to improve water quality. The two other important conditions of governance approaches for water quality improvement which were identified are the use of joint fact-finding to gain a shared perception of risks, and the use of explicit decision-making and close monitoring of outcomes (re. water quality improvement), both of which contribute to this enhanced connectivity
Co-Transport of Polycyclic Aromatic Hydrocarbons by Motile Microorganisms Leads to Enhanced Mass Transfer under Diffusive Conditions.
The
environmental chemodynamics of hydrophobic organic chemicals
(HOCs) are often rate-limited by diffusion in stagnant boundary layers.
This study investigated whether motile microorganisms can act as microbial
carriers that enhance mass transfer of HOCs through diffusive boundary
layers. A new experimental system was developed that allows (1) generation
of concentration gradients of HOCs under the microscope, (2) exposure
and direct observation of microorganisms in such gradients, and (3)
quantification of HOC mass transfer. Silicone O-rings were integrated
into a Dunn chemotaxis chamber to serve as sink and source for polycyclic
aromatic hydrocarbons (PAHs). This resulted in stable concentration
gradients in water (>24 h). Adding the model organism <i>Tetrahymena
pyriformis</i> to the experimental system enhanced PAH mass transfer
up to hundred-fold (benzoÂ[a]Âpyrene). Increasing mass transfer enhancement
with hydrophobicity indicated PAH co-transport with the motile organisms.
Fluorescence microscopy confirmed such transport. The effective diffusivity
of <i>T. pyriformis</i>, determined by video imaging microscopy,
was found to exceed molecular diffusivities of the PAHs up to four-fold.
Cell-bound PAH fractions were determined to range from 28% (naphthalene)
to 92% (pyrene). Motile microorganisms can therefore function as effective
carriers for HOCs under diffusive conditions and might significantly
enhance mobility and availability of HOCs
- …