1,144 research outputs found
Longitudinal and transversal spin dynamics of donor-bound electrons in fluorine-doped ZnSe: spin inertia versus Hanle effect
The spin dynamics of the strongly localized, donor-bound electrons in
fluorine-doped ZnSe epilayers is studied by pump-probe Kerr rotation
techniques. A method exploiting the spin inertia is developed and used to
measure the longitudinal spin relaxation time, , in a wide range of
magnetic fields, temperatures, and pump densities. The time of the
donor-bound electron spin of about 1.6 s remains nearly constant for
external magnetic fields varied from zero up to 2.5 T (Faraday geometry) and in
a temperature range K. The inhomogeneous spin dephasing time,
ns, is measured using the resonant spin amplification and Hanle
effects under pulsed and steady-state pumping, respectively. These findings
impose severe restrictions on possible spin relaxation mechanisms.Comment: 10 pages, 7 figure
HD DVD substrates for surface enhanced Raman spectroscopy analysis : fabrication, theoretical predictions and practical performance
Commercial HD DVDs provide a characteristic structure of encoding pits which were utilized to fabricate cost efficiently large area SERS substrates for chemical analysis. The study targets the simulation of the plasmonic structure of the substrates and presents an easily accessible fabrication process to obtain highly sensitive SERS active substrates. The theoretical simulation predicted the formation of supermodes under optimized illumination conditions, which were verified experimentally. First tests of the developed SERS substrates demonstrated their excellent potential for detecting vitamin A and pro- vitamin A at low concentration levels
Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe
Optically-induced nuclear spin polarization in a fluorine-doped ZnSe epilayer
is studied by time-resolved Kerr rotation using resonant excitation of
donor-bound excitons. Excitation with helicity-modulated laser pulses results
in a transverse nuclear spin polarization, which is detected as a change of the
Larmor precession frequency of the donor-bound electron spins. The frequency
shift in dependence on the transverse magnetic field exhibits a pronounced
dispersion-like shape with resonances at the fields of nuclear magnetic
resonance of the constituent zinc and selenium isotopes. It is studied as a
function of external parameters, particularly of constant and radio frequency
external magnetic fields. The width of the resonance and its shape indicate a
strong spatial inhomogeneity of the nuclear spin polarization in the vicinity
of a fluorine donor. A mechanism of optically-induced nuclear spin polarization
is suggested based on the concept of resonant nuclear spin cooling driven by
the inhomogeneous Knight field of the donor-bound electron.Comment: 12 pages, 11 figure
Children with severe acute asthma admitted to Dutch PICUs: A changing landscape
The number of children requiring pediatric intensive care unit (PICU) admission for severe acute asthma (SAA) around the world has increased. Objectives: We investigated whether this trend in SAA PICU admissions is present in the Netherlands. Methods: A multicenter retrospective cohort study across all tertiary care PICUs in the Netherlands. Inclusion criteria were children (2-18 years) hospitalized for SAA between 2003 and 2013. Data included demographic data, asthma diagnosis, treatment, and mortality. Results: In the 11-year study period 590 children (660 admissions) were admitted to a PICU with a threefold increase in the number of admissions per year over time. The severity of SAA seemed unchanged, based on the first blood gas, length of stay and mortality rate (0.6%). More children received highflow nasal cannula (P<0.001) and fewer children needed invasive ventilation (P<0.001). In 58% of the patients the maximal intravenous (IV) salbutamol infusion rate during PICU admission was 1mcg/kg/min. However, the number of patients treated with IV salbutamol in the referring hospitals increased significantly over time (P=0.005). The proportion of steroid-naïve patients increased from 35% to 54% (P=0.004), with a significant increase in both age groups (2-4 years [P=0.026] and 5-17 years [P=0.036]). Conclusions: The number of children requiring PICU admission for SAA in the Netherlands has increased. We speculate that this threefold increase is explained by an increasing number of steroid-naïve children, in conjunction with a lowered threshold for PICU admission, possibly caused by earlier use of salbutamol IV in the referring hospitals
Efficacy of a loading dose of IV salbutamol in children with severe acute asthma admitted to a PICU:a randomized controlled trial
The optimal dose regimen for intravenous (IV) treatment in children with severe acute asthma (SAA) is still a matter of debate. We assessed the efficacy of adding a salbutamol loading dose to continuous infusion with salbutamol in children admitted to a pediatric intensive care unit (PICU) with SAA. This multicentre, placebo-controlled randomized trial in the PICUs of four tertiary care children’s hospitals included children (2–18 years) with SAA admitted between 2017 and 2019. Children were randomized to receive either a loading dose IV salbutamol (15 mcg/kg, max. 750 mcg) or normal saline while on continuous salbutamol infusion. The primary outcome was the asthma score (Qureshi) 1 h after the intervention. Analysis of covariance models was used to evaluate sensitivity to change in asthma scores. Serum concentrations of salbutamol were obtained. Fifty-eight children were included (29 in the intervention group). Median baseline asthma score was 12 (IQR 10–13) in the intervention group and 11 (9–12) in the control group (p = 0.032). The asthma score 1 h after the intervention did not differ significantly between the groups (p = 0.508, β-coefficient = 0.283). The median increase in salbutamol plasma levels 10 min after the intervention was 13 μg/L (IQR 5–24) in the intervention group and 4 μg/L (IQR 0–7) in the control group (p = 0.001). Side effects were comparable between both groups. Conclusion: We found no clinical benefit of adding a loading dose IV salbutamol to continuous infusion of salbutamol, in children admitted to the PICU with SAA. Clinically significant side effects from the loading dose were not encountered.What is Known:• Pediatric asthma guidelines struggle with an evidence-based approach for the treatment of SAA beyond the initial steps of oxygen suppletion, repetitive administration of inhaled β2-agonists, and systemic steroids.• During an SAA episode, effective delivery of inhaled drugs is unpredictable due to severe airway obstruction.What is New:• This study found no beneficial effect of an additional loading dose IV salbutamol in children admitted to the PICU.• This study found no clinically significant side effects from the loading dose
Intraoperative Music to Promote Patient Outcome (IMPROMPTU):A Double-Blind Randomized Controlled Trial
Introduction: Perioperative music can have beneficial effects on postoperative pain, anxiety, opioid requirement, and the physiological stress response to surgery. The aim was to assess the effects of intraoperative music during general anesthesia in patients undergoing surgery for esophagogastric cancer. Materials and methods: The IMPROMPTU study was a double-blind, placebo-controlled, randomized multicenter trial. Adult patients undergoing surgery for stage II-III esophagogastric cancer were eligible. Exclusion criteria were a hearing impairment, insufficient Dutch language knowledge, corticosteroids use, or objection to hearing unknown music. Patients wore active noise-cancelling headphones intraoperatively with preselected instrumental classical music (intervention) or no music (control). Computerized randomization with centralized allocation, stratified according to surgical procedure using variable block sizes, was employed. Primary endpoint was postoperative pain on the first postoperative day. Secondary endpoints were postoperative pain during the first postoperative week, postoperative opioid requirement, intraoperative medication requirement, the stress response to surgery, postoperative complication rate, length of stay, and mortality, with follow-up lasting 30 d. Results: From November 2018 to September 2020, 145 patients were assessed and 83 randomized. Seventy patients (music n = 31, control n = 39) were analyzed. Median age was 70 [IQR 63–70], and 48 patients (69%) were male. Music did not reduce postoperative pain (numeric rating scale 1.8 (SD0.94) versus 2.0 (1.0), mean difference −0.28 [95% CI -0.76–0.19], P = 0.236). No statistically significant differences were seen in medication requirement, stress response, complication rate, or length of stay. Conclusions: Intraoperative, preselected, classical music during esophagogastric cancer surgery did not significantly improve postoperative outcome and recovery when compared to no music using noise-cancelling headphones.</p
Intraoperative Music to Promote Patient Outcome (IMPROMPTU):A Double-Blind Randomized Controlled Trial
Introduction: Perioperative music can have beneficial effects on postoperative pain, anxiety, opioid requirement, and the physiological stress response to surgery. The aim was to assess the effects of intraoperative music during general anesthesia in patients undergoing surgery for esophagogastric cancer. Materials and methods: The IMPROMPTU study was a double-blind, placebo-controlled, randomized multicenter trial. Adult patients undergoing surgery for stage II-III esophagogastric cancer were eligible. Exclusion criteria were a hearing impairment, insufficient Dutch language knowledge, corticosteroids use, or objection to hearing unknown music. Patients wore active noise-cancelling headphones intraoperatively with preselected instrumental classical music (intervention) or no music (control). Computerized randomization with centralized allocation, stratified according to surgical procedure using variable block sizes, was employed. Primary endpoint was postoperative pain on the first postoperative day. Secondary endpoints were postoperative pain during the first postoperative week, postoperative opioid requirement, intraoperative medication requirement, the stress response to surgery, postoperative complication rate, length of stay, and mortality, with follow-up lasting 30 d. Results: From November 2018 to September 2020, 145 patients were assessed and 83 randomized. Seventy patients (music n = 31, control n = 39) were analyzed. Median age was 70 [IQR 63–70], and 48 patients (69%) were male. Music did not reduce postoperative pain (numeric rating scale 1.8 (SD0.94) versus 2.0 (1.0), mean difference −0.28 [95% CI -0.76–0.19], P = 0.236). No statistically significant differences were seen in medication requirement, stress response, complication rate, or length of stay. Conclusions: Intraoperative, preselected, classical music during esophagogastric cancer surgery did not significantly improve postoperative outcome and recovery when compared to no music using noise-cancelling headphones.</p
Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score
\ua9 The Author(s) 2022. Published by Oxford University Press on behalf of BJS Society Ltd. BACKGROUND: Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score. METHODS: This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally. RESULTS: Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification. CONCLUSION: The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy
The association between hospital variation in curative treatment for esophagogastric cancer and health-related quality of life and survival
Background: As previous studies showed significant hospital variation in curative treatment of esophagogastric cancer, this study assesses the association between this variation and overall, cancer-specific and recurrence-free survival, and Health-Related Quality of Life (HRQoL). Methods: Patients diagnosed with potentially curable esophageal or gastric cancer between 2015 and 2018 as registered in the Netherlands Cancer Registry were included. Data on overall survival was available for all patients, data on cancer-specific and recurrence-free survival and HRQoL was available for subgroups. Patients were classified according to diagnosis in hospitals with low, medium or high probability of treatment with curative intent (LP, MP or HP). Multivariable models were used to assess the association between LP, MP and HP hospitals and HRQoL and survival. Results: This study includes 7,199 patients with esophageal, and 2,407 with gastric cancer. Overall and cancer-specific survival was better for patients diagnosed in HP versus LP hospitals for both esophageal (HR = 0.82, 95%CI:0.77–0.88 and HR = 0.82, 95%CI:0.75–0.91, respectively), and gastric cancer (HR = 0.82, 95%CI:0.73–0.92 and HR = 0.74, 95%CI:0.64–0.87, respectively). These differences disappeared after adjustments for treatment. Recurrence-free survival was worse for gastric cancer patients diagnosed in HP hospitals (HR = 1.50, 95%CI:1.14–1.96), which disappeared after adjustment for radicality of surgery. Minor, but no clinically relevant, differences in HRQoL were observed.Conclusions: Patients diagnosed in hospitals with a high probability of treatment with curative intent have a better overall and cancer-specific but not recurrence-free survival, while minor differences in HRQoL were observed.</p
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