This paper combines the data sets available today for 14C-age calibration of the last 60 ka. By stepwise synchronization of paleoclimate signatures, each of these sets of 14C-ages is compared with the U/Th-dated Chinese Hulu Cave speleothem records, which shows global paleoclimate change in high temporal resolution. By this synchronization we have established an absolute-dated Greenland-Hulu chronological framework, against which global paleoclimate data can be referenced, extending the 14C-age calibration curve back to the limits of the radiocarbon method. Based on this new, U/Th-based Greenland(Hulu) chronology, we confirm that the radiocarbon timescale underestimates calendar ages by several thousand years during most of Oxygen Isotope Stage 3. Major atmospheric 14C variations are observed for the period of the Middle to Upper Paleolithic transition, which has significant implications for dating the demise of the last Neandertals. The early part of "the transition" (with 14C ages > 35.0 ka 14C BP) coincides with the Laschamp geomagnetic excursion. This period is characterized by highly-elevated atmospheric 14C levels. The following period ca. 35.0-32.5 ka 14C BP shows a series of distinct large-scale 14C age inversions and extended plateaus. In consequence, individual archaeological 14C dates older than 35.0 ka 14C BP can be age-calibrated with relatively high precision, while individual dates in the interval 35.0-32.5 ka 14C BP are subject to large systematic age-'distortions,' and chronologies based on large data sets will show apparent age-overlaps of up to ca. 5,000 cal years. Nevertheless, the observed variations in past 14C levels are not as extreme as previously proposed ("Middle to Upper Paleolithic dating anomaly"), and the new chronological framework leaves ample room for application of radiocarbon dating in the age-range 45.0-25.0 ka 14C BP at high temporal resolution.
To evaluate the possibility of applying the Third Molar Eruption Predictor to all panoramic radiographs.
Panoramic radiographs were retrospectively analyzed from a 4-year follow-up study of third molars carried out at the University of Copenhagen, Denmark. The radiographs, taken at a mean age of 20.6 years, included 45 unerupted or partially erupted mandibular third molars in 28 subjects. Because the device was calibrated both with simple proportions and by use of the methods of Bayes' Decision Theory, the separation point of the device was therefore adjusted at 12 mm from the distal surface of the second molar.
The predictions of future eruption or impaction made with the calibrated device and the actual clinical outcome 4 years later were in conformity for 80% of the mandibular third molars.
The Third Molar Eruption Predictor may be applied to all panoramic radiographs, but it seems to require calibration before use.
Although inadequate antimicrobial therapy has been demonstrated in multiple studies to increase the risk for death in bacterial infections, few data investigating the effect of antifungal therapy on outcome of serious fungal disease are available. We sought to assess the adequacy of empirical therapy and its effect on mortality in invasive Candida species infections.
Population-based surveillance of all patients with Candida spp. cultured from blood and/or cerebrospinal fluid was conducted. Adequacy of empirical therapy was assessed according to published guidelines.
During a 5 year period, 207 patients had an invasive Candida spp. infection identified; in 199 cases (96%) adequate data were available for assessment of treatment and outcome at hospital discharge. One hundred and three (52%) cases were due to Candida albicans, 44 (22%) were due to Candida glabrata and the remainder were due to other species. Between the time of culture draw and reporting of a positive culture, only 64 (32%) patients were treated with empirical therapy; this was deemed adequate in 51 (26%). Patients who received adequate empirical therapy had a significant decrease in crude mortality [14/51 (27%) versus 68/148 (46%); risk ratio 0.60 (95% confidence interval 0.37-0.96); P = 0.02]. After adjusting for age and the need for intensive care unit admission in logistic regression analysis, the use of adequate empirical therapy was independently associated with a reduced risk for death [odds ratio 0.46 (95% confidence interval 0.22-1.00); P = 0.05].
Adequate empirical therapy is used in a minority of patients with invasive Candida spp. infections but is associated with improved survival.
BACKGROUND: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. METHODS: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF(6)) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6-13 years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH(2)O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to -20 cmH(2)O. (CC/EEV >1 indicates that airway closure might occur during tidal breathing). Furthermore, a measure of uneven ventilation, multiple breath alveolar mixing efficiency (MBAME), was obtained. RESULTS: Airway closure within the tidal volume (CC/EEV >1) was observed in four and eight children (not significant, NS) after 20 and 30 cmH(2)O inflation, respectively. However, CC(30)/EEV was >CC(20)/EEV in all children (P
Here, we use a unique long-term data set on total organic carbon (TOC) fluxes, its climatic drivers and effects of land management from a large boreal watershed in northern Finland. TOC and runoff have been monitored at several sites in the Simojoki watershed (3160 km(2) ) since the early 1960s. Annual TOC fluxes have increased significantly together with increased inter-annual variability. Acid deposition in the area has been low and has not significantly influenced losses of TOC. Forest management, including ditching and clear felling, had a minor influence on TOC fluxes - seasonal and long-term patterns in TOC were controlled primarily by changes in soil frost, seasonal precipitation, drought, and runoff. Deeper soil frost led to lower spring TOC concentrations in the river. Summer TOC concentrations were positively correlated with precipitation and soil moisture not temperature. There is some indication that drought conditions led to elevated TOC concentrations and fluxes in subsequent years (1998-2000). A sensitivity analysis of the INCA-C model results showed the importance of landscape position, land-use type, and soil temperature as controls of modeled TOC concentrations. Model predictions were not sensitive to forest management. Our results are contradictory to some earlier plot-scale and small catchment studies that have shown more profound forest management impacts on TOC fluxes. This shows the importance of scale when assessing the mechanisms controlling TOC fluxes and concentrations. The results highlight the value of long-term multiple data sets to better understand ecosystem response to land management, climate change and extremes in northern ecosystems.
BACKGROUND: Photoscreening can allow early detection of amblyopia. The Gateway DV-S20, and similar models of miniature, digital flash cameras, have similar optical dimensions to existing photoscreeners for less than $200. METHODS: These cameras were calibrated on known, threshold amblyogenic refractive errors induced by placing minus and toric contact lenses on a normal subject's left eye. The DV-S20 was then applied to known amblyopic patients. Students under age 7 were vision screened with patched acuity and sequential photoscreeners (MTI and Gateway). RESULTS: The digital cameras and the MTI photoscreeners produced similar magnitude interpretable crescents for amblyopiagenic refractive errors. They had very similar validation with sensitivities of 80-90% and specificities of 98% for serious eye disorders in known patients and school-aged children. CONCLUSION: Combined with careful interpretation, pocket-sized, digital flash cameras provide a portable and inexpensive digital alternative for pediatric photoscreening. A category 3 CPT code (0065T) can be used for this valid, public health technique: Amblyopia Detection By Camera (ADBC).
A reliable and sensitive graphite furnace atomic absorption spectrometry (GFAAS) method with Zeeman background correction was developed for the analysis of aluminium in serum and urine in the biological monitoring of aluminium exposure. The method is based on platform atomisation in pyrolytically coated graphite tubes after fourfold dilution with nitric acid. For serum analysis, a matrix matched standard curve is prepared and for urine the method of standard additions is used. The within-run imprecision (C.V.) for serum and urine was 3% and 5%, and the between-day imprecision, 6% and 7.2%, at a concentration level of 4.0 mumol/l. The between-day imprecision for urinary aluminium was 15.7% at a concentration level of 0.24 mumol/l. The detection limits were 0.02 mumol/l for serum and 0.07 mumol/l for urine. During 1 year of participation in TEQAS external quality assessment scheme of the Robens Institute for Health and Safety (Guildford, UK) for serum aluminium the maximum cumulative performance score was achieved. For urinary aluminium a certificate in the external quality control scheme of the German Society of Occupational Medicine was obtained. The mean concentration of aluminium in a non-exposed population, who did not use antacid drugs, was 0.06 mumol/l (S.D. 0.03, range 0.02-0.13, n = 21) in serum, and 0.33 mumol/l (S.D. 0.18, range 0.07-0.82, n = 44) in urine. The upper reference limit for aluminium in a healthy, non-exposed population was estimated to be 0.1 mumol/l in serum and 0.6 mumol/l in urine.
An uncertainty budget was constructed for the measurement of ethanol in blood by headspace gas chromatography. The uncertainty budget, covering the analytical range of ethanol concentrations up to 3.00 g/kg, included analytical uncertainty components, traceability uncertainty components, and effects caused by interindividual variation in blood water content. The analytical combined standard uncertainty was estimated from duplicate measurements of real samples and included contributions from headspace recovery, variation between columns, injection, repeatability of analytical signals, and statistical uncertainty of the calibration function. The traceability uncertainty was estimated in a sub-budget based on information about the calibrator and about the preparation of the aqueous standards. Two uncertainty components depended on the interindividual variation in blood water content. First, it caused uncertainty on the density of the blood, and second, it had an effect on the gas phase concentration of ethanol when doing the headspace sampling. These effects as well as their covariance were included in the uncertainty budget. For fresh blood samples, the analytical uncertainty was the dominating uncertainty component, accounting for approximately 90% of the variance. For blood samples collected 100 h postmortem, the interindividual variation in blood water content was the largest uncertainty component. It was demonstrated that subtracting a "safety margin" of 0.1 g/kg from the results was sufficient to keep the risk of committing a type 1 error below 0.1% in ethanol concentrations ranging up to 2 g/kg for fresh blood samples. This risk was higher for postmortem blood samples because of the higher uncertainty of measurement, but still less than approximately 1.4%.
Analytical methods are generally developed and optimized for specific commodities. Total Diet Studies, representing typical food products 'as consumed', pose an analytical challenge since every food product is different. In order to address this technical challenge, a selective and sensitive analytical method was developed suitable for the quantitation of ochratoxin A (OTA) in Canadian Total Diet Study composites. The method uses an acidified solvent extraction, an immunoaffinity column (IAC) for clean-up, liquid chromatography-tandem mass spectrometry (LC-MS/MS) for identification and quantification, and a uniformly stable isotope-labelled OTA (U-[(13)C(20)]-OTA) as an internal recovery standard. Results are corrected for this standard. The method is accurate (101% average recovery) and precise (5.5% relative standard deviation (RSD)) based on 17 duplicate analysis of various food products over 2 years. A total of 140 diet composites were analysed for OTA as part of the Canadian Total Diet Study. Samples were collected at retail level from two Canadian cities, Quebec City and Calgary, in 2008 and 2009, respectively. The results indicate that 73% (102/140) of the samples had detectable levels of OTA, with some of the highest levels of OTA contamination found in the Canadian bread supply.
To assess the safety of reusing single-use intraaortic balloon devices (IABs), 112 used devices were investigated in terms of physical integrity, gas leakage inspection, mechanical performance, surface chemistry and morphology, and physical stability. These IABs were all used clinically only once, and the duration of the IABs in vivo ranged from 6 to 312 h. Macroscopic examination of the balloons and the outer catheters revealed no obvious change in either shape or color. No discernible abrasions or cracks were observed on the balloons. However, 61% of the balloons were creased, and 40% of the central lumens and 21% of the sheaths showed visible bending flaws. Moreover, 65% of the balloons and 38% of the central lumens were contaminated by visible residual organic debris. The physical integrity of each device was verified in a specially designed leakage-fatigue tester for 72 h. Ninety-seven percent of the devices passed the leakage inspection. Stress-strain testing, differential scanning calorimetry, attenuated total reflection-Fourier transform infrared, and scanning electron microscopy analyses clearly indicated that there were no significant differences in the mechanical properties, bulk material morphology, surface chemistry, and external surface morphology between the used balloons and virgin controls. Although some surface modifications occurred on the internal side of the balloons, the external surfaces of most balloons suffered no trauma. Most of the used IABs examined in this study maintained physical and mechanical properties similar to those of the virgin devices. The chemistry of the balloon material was stable after short-term in vivo use. However, it does not seem possible to establish a rigorous protocol of cleaning, sterilization, and inspection to guarantee a safer reuse of these devices. The presence of residual organic debris that cannot be eliminated results in an imperative preclusion not to reuse the IABs.