Piezoelectric quartz crystals have long been used as frequency and time standards accurate to 1 part in 108 or better. These stable elements become selective gas detectors when coated with various materials. Crystals coated with gas chromatographic substrates produce gas chromatographic detectors which have several advantages: Sensitivity increases with solute boiling point, detectors can be made selective to compound type and respond in 0.05 second, and the output signal is a frequency which simplifies integration of peak areas and digital presentation of the data. The crystals used in this work were quartz plates Y2 inch in diameter, 7.3 mils thick, that vibrate at 9 Me. A readily measured signal of 1 c.p.s. corresponds to a weight increase of about 10~9 gram. Coated-crystal moisture detectors sensitive to 0.1 p.p.m. are now commercially available. Hydrocarbon detectors sensing as little as 1 p.p.m. of xylene have been tested.
ObjectivesDetermine the real-world difference between 2 groups of patients with severe aortic stenosis and similar baseline comorbidities: surgical turn down (STD) patients, who were managed medically prior to the availability of transcatheter aortic valve implantation (TAVI) following formal surgical outpatient assessment, and patients managed with a TAVI implant.DesignRetrospective cohort study from real-world data.SettingElectronic patient letters were searched for patients with a diagnosis of severe aortic stenosis and a formal outpatient STD prior to the availability of TAVI (1999–2009). The second group comprised the first 90 cases of TAVI in South Wales (2009 onwards). 2 years prior to and 5 years following TAVI/STD were assessed. Patient data were pseudoanonymised, using the Secure Anonymized Information Linkage (SAIL) databank, and extracted from Office National Statistics (ONS), Patient-Episode Database for Wales (PEDW) and general practitioner databases.Population90 patients who had undergone TAVI in South Wales, and 65 STD patients who were medically managed.Main outcome measuresSurvival, hospital admission frequency and length of stay, primary care visits, and cost-effectiveness.ResultsTAVI patients were significantly older (81.8 vs 79.2), more likely to be male (59.1% vs 49.3%), baseline comorbidities were balanced. Mortality in TAVI versus STD was 28% vs 70% at 1000 days follow-up. There were significantly more hospital admissions per year in the TAVI group prior to TAVI/STD (1.5 (IQR 1.0–2.4) vs 1.0 IQR (0.5–1.5)). Post TAVI/STD, the TAVI group had significantly lower hospital admissions (0.3 (IQR 0.0–1.0) vs 1.2 (IQR 0.7–3.0)) and lengths of stay (0.4 (IQR 0.0–13.8) vs 11.0 (IQR 2.5–28.5), p<0.05). The incremental cost-effectiveness ratio (ICER) for TAVI was £10 533 per quality-adjusted life year (QALY).ConclusionsTAVI patients were more likely to survive and avoid hospital admissions compared with the medically managed STD group. The ICER for TAVI was £10 533 per QALY, making it a cost-effective procedure.
Who with sleep seizures is safe to drive? Driving law is controversial; ineligibility varies between individual US states and EU countries. Current UK driving law is strongly influenced by a single-centre study from 1974 where most participants were not taking antiepileptic drugs (AEDs). However, pure sleep-related epilepsy is often fully controlled on medication, and its withdrawal can provoke awake seizures. This systematic review asked, 'What is the risk of awake seizures in pure sleep-related epilepsy?' 9885 titles were identified; 2312 were excluded (not human or adult); 40 full texts were reviewed; six papers met our inclusion criteria; each of these six studies had a different pure sleep-related epilepsy definition. Using the largest prospective study, we were able to calculate next year's awake seizure chance (treated with antiepileptic medication). This was maximal in the second year: 5.7% (95% CI 3.0 to 10
The Saskatchewan Health Dental Plan (SHDP) is a publicly funded dental insurance program for children between the ages of five and 16 years residing in the province. In 1981, fissure sealants were added as a covered expense. Until September 1, 1987, sealants and other dental treatments covered under the SHDP were provided to schoolchildren by dental therapists in dental clinics established in elementary schools throughout the province. After September 1, 1987, the provision of dental services was transferred to private practitioners in the province. The objectives of this study were to (1) estimate the retention rates of sealants after one, two, and three years of placement; and (2) conduct a longitudinal followup of sealed and unsealed sound teeth to measure the effectiveness of sealants in reducing dental caries incidence. Relative to the first objective, a cohort of children was identified and comparisons were carried out for the periods of 1982-83, 1982-84, and 1982-85. For the last objective, a longitudinal evaluation of effectiveness was carried out only for children five to seven years of age in 1981. Saskatchewan children, who experienced higher caries prevalence than children in the United States, had the highest caries increments on occlusal surfaces of posterior teeth. About 79 percent of the sealants applied by dental therapists were retained three years after application. Sealed teeth experienced 46 percent less caries than unsealed teeth four years after the application of sealants.(ABSTRACT TRUNCATED AT 250 WORDS)
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