139 research outputs found
On the Trade-Off Between Quality Factor and Tuning Ratio in Tunable High-Frequency Capacitors
A benchmark of tunable and switchable devices at microwave frequencies is presented on the basis of physical limitations to show their potential for reconfigurable cellular applications. Performance limitations are outlined for each given technology focusing on the quality factor (Q) and tuning ratio (eta) as figures of merit. The state of the art in terms of these figures of merit of several tunable and switchable technologies is visualized and discussed. If the performance of these criteria is not met, the application will not be feasible. The quality factor can typically be traded off for tuning ratio. The benchmark of tunable capacitor technologies shows that transistor-switched capacitors, varactor diodes, and ferroelectric varactors perform well at 2 GHz for tuning ratios below 3, with an advantage for GaAs varactor diodes. Planar microelectromechanical capacitive switches have the potential to outperform all other technologies at tuning ratios higher than 8. Capacitors based on tunable dielectrics have the highest miniaturization potential, whereas semiconductor devices benefit from the existing manufacturing infrastructure
Guillain-Barré Syndrome-related campylobacter jejuni in Bangladesh: ganglioside mimicry and cross-reactive antibodies
BACKGROUND:
<br/>
Campylobacter jejuni is the predominant antecedent infection in Guillain-Barré syndrome (GBS). Molecular mimicry and cross-reactive immune responses to C. jejuni lipo-oligosaccharides (LOS) precipitate the development of GBS, although this mechanism has not been established in patients from developing countries. We determined the carbohydrate mimicry between C. jejuni LOS and gangliosides, and the cross-reactive antibody response in patients with GBS in Bangladesh.<br/>
METHODOLOGY:<br/>
Sera from 97 GBS patients, and 120 neurological and family controls were tested for antibody reactivity against LOS from C. jejuni isolates from GBS patients in Bangladesh (BD-07, BD-39, BD-10, BD-67 and BD-94) by enzyme-linked immunosorbent assay (ELISA). Cross-reactivity to LOS was determined by ELISA. The LOS outer core structures of C. jejuni strains associated with GBS/MFS were determined by mass spectrometry.<br/>
PRINCIPLE FINDINGS:<br/>
IgG antibodies to LOS from C. jejuni BD-07, BD-39, BD-10, and BD-67 IgG antibodies were found in serum from 56%, 58%, 14% and 15% of GBS patients respectively, as compared to very low frequency (<3%) in controls (p<0.001). Monoclonal antibodies specific for GM1 and GD1a reacted strongly with LOS from the C. jejuni strains (BD-07 and BD-39). Mass spectrometry analysis confirmed the presence of GM1 and GD1a carbohydrate mimics in the LOS from C. jejuni BD-07 and BD-39. Both BD-10 and BD-67 express the same LOS outer core, which appears to be a novel structure displaying GA2 and GD3 mimicry. Up to 90-100% of serum reactivity to gangliosides in two patients (DK-07 and DK-39) was inhibited by 50 µg/ml of LOS from the autologous C. jejuni isolates. However, patient DK-07 developed an anti-GD1a immune response while patient DK-39 developed an anti-GM1 immune response.<br/>
CONCLUSION:<br/>
Carbohydrate mimicry between C. jejuni LOS and gangliosides, and cross-reactive serum antibody precipitate the majority of GBS cases in Bangladesh
Intrathecal hydrophilic opioids for abdominal surgery: a meta-analysis, meta-regression, and trial sequential analysis
Background: Intrathecal hydrophilic opioids decrease systemic opioid consumption after abdominal surgery and potentially facilitate enhanced recovery. A meta-analysis is needed to quantify associated risks and benefits. Methods: A systematic search was performed to find RCTs investigating intrathecal hydrophilic opioids in abdominal surgery. Caesarean section and continuous regional or neuraxial techniques were excluded. Several subgroup analyses were prespecified. A conventional meta-analysis, meta-regress
The effect of midazolam as premedication on the quality of postoperative recovery after laparotomy: a randomized clinical trial
Purpose Despite the uncertain effects of anxiolytic
premedication with benzodiazepines on the quality of
postoperative recovery, perioperative benzodiazepine
administration is still a common practice in many
hospitals. We evaluated the effect of premedication with
midazolam on the quality of recovery in hospitalized
patients undergoing a laparotomy.
Methods We conducted a single-centre randomized
placebo-controlled, double-blinded clinical trial from
July 2014 to September 2015. We included 192 patients
aged [ 18 yr scheduled for elective laparotomy with a
planned postoperative stay of C three days. Participants
were randomized into two groups to receive either
midazolam 3 mg or sodium chloride 0.9% intravenously
as premedication prior to surgery. Patients were followed
up for up to one week after surgery. The primary outcome
was the Quality of Recovery-40 (QoR-40) score on
postoperative day (POD) 3. The secondary outcomes
included the QoR-40 score on POD 7, and the StateTrait Anxiety Inventory, State-Trait Anger Scale,
Multidimensional Fatigue Inventory, and the Hospital
Anxiety and Depression Scale scores.
Results The mean (standard deviation) postoperative
QoR-40 scores on POD 3 were not significantly different
in the midazolam group compared with controls [166.4
(17.0) vs 163.9 (19.8), respectively; mean difference, 2.3;
95% confidence interval, - 2.9 to 8.4; P = 0.35]. There
were no between-group differences in any of the secondary
outcomes.
Conclusions Administration of midazolam as
premedication for laparotomy patients did not improve
the quality of recovery up to one week after surgery.
General prescription of midazolam as premedication can
be questioned and might only suit some patients.
Trial registration www.clinicaltrials.gov (NCT01993459);
registered 29 October, 2013
Validating differential volatilome profiles in Parkinson’s disease
Contains fulltext :
231972.pdf (Publisher’s version ) (Open Access
In-depth exploration of the photophysics of a trinuclear palladium complex
Contains fulltext :
128388.pdf (publisher's version ) (Open Access
On the Trade-Off Between Quality Factor and Tuning Ratio in Tunable High-Frequency Capacitors
Can Campylobacter coli induce Guillain-Barré syndrome?
Campylobacter jejuni enteritis is the most frequently identified infection preceding the Guillain-Barr\ue9 syndrome (GBS) and neural damage is thought to be induced through molecular mimicry between C. jejuni lipo-oligosaccharide (LOS) and human gangliosides. It has been questioned whether or not other Campylobacter species, including C. curvus, C. upsaliensis and C. coli, could be similarly involved. This is relevant because it would imply that bacterial factors considered important in the aetiology of GBS crossed species barriers. Two prior reports have appeared where C. coli was putatively associated with a case of GBS.Peer reviewed: YesNRC publication: Ye
Genetic biomarkers for intravenous immunoglobulin response in chronic inflammatory demyelinating polyradiculoneuropathy
Background and purpose Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a clinical and electrophysiological heterogeneous immune-mediated polyneuropathy. Intravenous immunoglobulin (IVIg), corticosteroids, and plasma exchange are proven effective treatments for CIDP. The clinical response to IVIg is variable between patients and currently unexplained. Finding biomarkers related to treatment response can help to understand the diversity of CIDP and personalise treatment choice.Methods We investigated whether genetic variation between patients may explain some of these differences in treatment response. Based on previous publications, we selected six candidate genes that might affect immune and axonal functions, IVIg metabolism, and treatment response in CIDP. Genetic variants were assessed in 172 CIDP patients treated with at least one course of IVIg (2 g/kg). A response to IVIg was defined by >= 1 grade improvement on the modified Rankin Scale. Blood samples were tested for variations in CNTN2, PRF1, FCGRT, FCGR2B, GJB1, and SH2D2A genes.Results In univariate analysis, patients with the FCGR2B promoter variant 2B.4/2B.1 responded more often to IVIg than patients with the 2B.1/2B.1 variant (odds ratio [OR] = 6.9, 95% confidence interval [CI] = 1.6-30; p = 0.003). Patients with the p.(Ala91Val) variant of PRF1 were less often IVIg responsive (OR = 0.34, 95% CI = 0.13-0.91; p = 0.038). In multivariate analysis, both PRF1 and FCGR2B showed discriminative ability to predict the chance of IVIg response (area under the curve = 0.67).Conclusions Variations in PRF1 and the promoter region of FCGR2B are associated with the response to IVIg in CIDP. These findings, which require validation, are a first step towards the understanding of the heterogeneity in the treatment response in CIDP.Genetics of disease, diagnosis and treatmen
Environmentally Persistent Free Radicals (EPFRs). 3. Free versus Bound Hydroxyl Radicals in EPFR Aqueous Solutions
Additional experimental evidence is presented for in vitro generation of hydroxyl radicals because of redox cycling of environmentally persistent free radicals (EPFRs) produced after adsorption of 2-monochlorophenol at 230 °C (2-MCP-230) on copper oxide supported by silica, 5% Cu(II)O/silica (3.9% Cu). A chemical spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed. Experiments in spiked O17 water have shown that ∼15% of hydroxyl radicals formed as a result of redox cycling. This amount of hydroxyl radicals arises from an exogenous Fenton reaction and may stay either partially trapped on the surface of particulate matter (physisorbed or chemisorbed) or transferred into solution as free OH. Computational work confirms the highly stable nature of the DMPO–OH adduct, as an intermediate produced by interaction of DMPO with physisorbed/chemisorbed OH (at the interface of solid catalyst/solution). All reaction pathways have been supported by ab initio calculations
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