3,411 research outputs found
Estimation of Saturation of Permanent-Magnet Synchronous Motors Through an Energy-Based Model
We propose a parametric model of the saturated Permanent-Magnet Synchronous
Motor (PMSM) together with an estimation method of the magnetic parameters. The
model is based on an energy function which simply encompasses the saturation
effects. Injection of fast-varying pulsating voltages and measurements of the
resulting current ripples then permit to identify the magnetic parameters by
linear least squares. Experimental results on a surface-mounted PMSM and an
interoir magnet PMSM illustrate the relevance of the approach.Comment: IEMDC-2011 (preliminary version
Charge Distribution on Annealed Polyelectrolytes
We investigate the equilibrium charge distribution along a single annealed
polyelectrolyte chain under different conditions. The coupling between the
conformation of the chain and the local charge distribution is described for
various solvent qualities and salt concentration. In salt free solution, we
find a slight charge depletion in the central part of the chain: the charges
accumulate at the ends. The effect is less important if salt is added to the
solution since the charge inhomogeneity is localized close to the chain ends
over a distance of order of the Debye length. In the case of poor solvent
conditions we find a different charging of beads and strings in the framework
of the necklace model. This inhomogeneity leads to a charge instability and a
first order transition between spherical globules and elongated chains.Comment: 20 pages, 4 figure
mRNA fusion constructs serve in a general cell‐based assay to profile oligonucleotide activity
A cellular assay has been developed to allow measurement of the inhibitory activity of large numbers of oligonucleotides at the protein level. The assay is centred on an mRNA fusion transcript construct comprising of a full‐length reporter gene with a target region of interest inserted into the 3′‐untranslated region. Luciferase and fluorescent reporter genes were used in the constructs. The insert can be from multiple sources (uncharacterised ESTs, partial or full‐length genes, genes from alternate species, etc.). Large numbers of oligonucleotides were screened for antisense activity against a number of such constructs bearing different reporters, in different cell lines and the inhibitory profiles obtained were compared with those observed through screening the oligonucleotides against the corresponding endogenous genes assayed at the mRNA level. A high degree of similarity in the profiles was obtained indicating that the fusion constructs are suitable surrogates for the endogenous messages for characterisation of antisense oligonucleotides (ASOs). Furthermore, the results support the hypothesis that the secondary structure of mRNAs are divided into domains, the nature of which is determined by primary nucleotide sequence. Oligonucleotides whose activity is dependent on the local structure of their target mRNAs (e.g. ASOs, short interfering RNAs) can be characterised via such fusion RNA construct
Safety of low-dose spironolactone administration in chronic haemodialysis patients
Background. Prevention of cardiovascular diseases is essential in chronic haemodialysis patients. Recently, low-dose spironolactone has been shown to decrease cardiovascular mortality in patients with severe heart failure. However, since haemodialysis patients are prone to hyperkalaemia, a known side effect of spironolactone, this treatment is not used in this population. We performed a study to assess whether low-dose spironolactone (3 × 25 mg/week) could be administered without inducing hyperkalaemia in haemodialysis patients. Methods. The study design included a 2-week baseline period, followed by a 4-week treatment period in which doses of spironolactone were started at 12.5 mg three times/week for 2 weeks, then increased to 25 mg three times/week, and followed by a 2-week wash-out period. Fourteen patients receiving low-dose spironolactone after each dialysis were compared with 21 haemodialysis patients (control group). Results. Low-dose spironolactone did not change mean serum potassium (4.9 ± 0.7 vs 4.9 ± 0.3 mmol/l: control). The mean plasma canrenone level induced by administration of spironolactone 25 mg three times/week in the 14 treated patients was 13 ± 5.3 ng/ml. Serum aldosterone was not significantly modified by the administration of spironolactone in these patients [before, median 0.35; interquartile range (IQR) 0.11-2.83 nmol/l vs after, median 0.22; IQR 0.12-0.60 nmol/l, NS]. Dietary potassium intake and the use of ion-exchange resin, angiotensin-converting enzyme inhibitors and β-blockers were similar for the two groups throughout the study. Conclusion. This non-randomized and non-blinded study shows that administration of 25 mg spironolactone thrice weekly is not associated with an increased frequency of hyperkalaemia in haemodialysis patients when they are carefully monitored. More studies are required, however, before concluding that spironolactone administration is safe in the chronic haemodialysis populatio
Resolving debris discs in the far-infrared: early highlights from the DEBRIS survey
We present results from the earliest observations of DEBRIS, a Herschel Key
Programme to conduct a volume- and flux-limited survey for debris discs in
A-type through M-type stars. PACS images (from chop/nod or scan-mode
observations) at 100 and 160 micron are presented toward two A-type stars and
one F-type star: beta Leo, beta UMa and eta Corvi. All three stars are known
disc hosts. Herschel spatially resolves the dust emission around all three
stars (marginally, in the case of beta UMa), providing new information about
discs as close as 11 pc with sizes comparable to that of the Solar System. We
have combined these data with existing flux density measurements of the discs
to refine the SEDs and derive estimates of the fractional luminosities,
temperatures and radii of the discs.Comment: to be published in A&A, 5 pages, 2 color figure
Effects of increase in fish oil intake on intestinal eicosanoids and inflammation in a mouse model of colitis
BACKGROUND: Inflammatory bowel diseases (IBD) are chronic intestinal inflammatory diseases affecting about 1% of western populations. New eating behaviors might contribute to the global emergence of IBD. Although the immunoregulatory effects of omega-3 fatty acids have been well characterized in vitro, their role in IBD is controversial. METHODS: The aim of this study was to assess the impact of increased fish oil intake on colonic gene expression, eicosanoid metabolism and development of colitis in a mouse model of IBD. Rag-2 deficient mice were fed fish oil (FO) enriched in omega-3 fatty acids i.e. EPA and DHA or control diet for 4 weeks before colitis induction by adoptive transfer of naïve T cells and maintained in the same diet for 4 additional weeks. Onset of colitis was monitored by colonoscopy and further confirmed by immunological examinations. Whole genome expression profiling was made and eicosanoids were measured by HPLC-MS/MS in colonic samples. RESULTS: A significant reduction of colonic proinflammatory eicosanoids in FO fed mice compared to control was observed. However, neither alteration of colonic gene expression signature nor reduction in IBD scores was observed under FO diet. CONCLUSION: Thus, increased intake of dietary FO did not prevent experimental colitis
Lung transplantation after allogeneic stem cell transplantation : a pan-European experience
Late-onset noninfectious pulmonary complications (LONIPCs) affect 6% of allogeneic stem cell transplantation (SCT) recipients within 5 years, conferring subsequent 5-year survival of 50%. Lung transplantation is rarely performed in this setting due to concomitant extrapulmonary morbidity, excessive immunosuppression and concerns about recurring malignancy being considered contraindications. This study assesses survival in highly selected patients undergoing lung transplantation for LONIPCs after SCT. SCT patients undergoing lung transplantation at 20 European centres between 1996 and 2014 were included. Clinical data pre- and post-lung transplantation were reviewed. Propensity score-matched controls were generated from the Eurotransplant and Scandiatransplant registries. Kaplan-Meier survival analysis and Cox proportional hazard regression models evaluating predictors of graft loss were performed. Graft survival at 1, 3 and 5 years of 84%, 72% and 67%, respectively, among the 105 SCT patients proved comparable to controls (p=0.75). Sepsis accounted for 15 out of 37 deaths (41%), with prior mechanical ventilation (HR 6.9, 95% CI 1.0-46.7; p Lung transplantation outcomes following SCT were comparable to other end-stage diseases. Lung transplantation should be considered feasible in selected candidates. No SCT-specific factors influencing outcome were identified within this carefully selected patient cohort.Peer reviewe
The SARS algorithm: detrending CoRoT light curves with Sysrem using simultaneous external parameters
Surveys for exoplanetary transits are usually limited not by photon noise but
rather by the amount of red noise in their data. In particular, although the
CoRoT spacebased survey data are being carefully scrutinized, significant new
sources of systematic noises are still being discovered. Recently, a
magnitude-dependant systematic effect was discovered in the CoRoT data by Mazeh
& Guterman et al. and a phenomenological correction was proposed. Here we tie
the observed effect a particular type of effect, and in the process generalize
the popular Sysrem algorithm to include external parameters in a simultaneous
solution with the unknown effects. We show that a post-processing scheme based
on this algorithm performs well and indeed allows for the detection of new
transit-like signals that were not previously detected.Comment: MNRAS accepted. 5 pages, 3 figure
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