Evaluation of CPAP mask performance during 3 years of mask usage: time for reconsideration of renewal policies?

BackgroundContinuous positive airway pressure (CPAP) mask renewal policies vary inside and between countries. There are no independent studies on the optimal mask renewal frequency. We aimed to evaluate CPAP mask function over time in a real-life clinical setting, and to compare the results against current renewal policies.MethodsDaily performance data of 1846 CPAP masks (65% nasal, 22% nasal pillows, 12% oronasal) were recorded from 450 participants (68% male, mean age 59 years) with obstructive sleep apnoea. The unintentional leak, Apnoea-Hypopnoea Index (CPAP-AHI) and usage data were exported from the CPAP device.ResultsOf 656 324 nights of CPAP usage, the mean renewal time was 497 days (SD 327), mean leak 5.7 L/min (SD 8.1) and CPAP-AHI 3.8 events/h (SD 3.6). The difference in mean leak between one (5.2 L/min, SD 7.5), 12 (6.0 L/min, SD 10.2) and 24 months (5.8 L/min, SD 7.5) was minimal (p=0.59). Mean CPAP-AHI remained normal and unchanged in nasal masks and pillows up to 30 months, and was highest in oronasal masks. Different mask manufacturers performed similarly. Masks’ daily or total usage did not affect the results. Shifting the mask renewal policy to 24 months could reduce the mask-related cost up to 50%–88%.ConclusionsNasal masks and pillows could be used at least 2 years without significant changes in unintentional leak and CPAP-AHI. We suggest updating the mask renewal policies of nasal masks and pillows; results on oronasal masks and other manufacturers CPAP devices need further verification.

PENGARUH WAKTU PEMBAHARUAN SADAPAN POHON PINUS (Pinus merkusii) PADA UMUR BERBEDA TERHADAP PRODUKTIVITAS GETAH

Pine sap exploitation is growing because demand for pine sap in Indonesia and the world is increasing. Pine sap productivity is influenced by several factors including tapping, tree species, diameter, and age of stands. In the tapping method, one of them is the renewal time of tapping with the quarre system which is supposed to save the tapping area and get the maximum sap. This paper studies the effect of the renewal of the pine tree tapping at different ages on the productivity of the sap. The proposed method is a survey with a purposive sample determination with 3 different treatments, namely treatment A of the 3-day quarre renewal, treatment B of the 5-day quarre renewal, and treatment of the renewal of the 7-day quarre by administering stimulants. Performed at different age classes IV, VI, and VIII. Field observational data is then processed using a factorial Completely Randomized Plan analysis with two factors. The results showed that the renewal of quarre had a significant effect on the average productivity of pine tree sap at 95% confidence intervals (α = 0.05). The highest average productivity on treatment B renewal of 5 days quarre was 12.17 grams /quarre/day at age classes VI and the lowest average productivity was at treatment C of renewal of 7 days with 4.61 grams /quarre/day at age classes IV.

Quantitative Modeling of Azacitidine Resistance in Patients with Myelodysplastic Syndrome Identifies Distinct Phenotypes of Disease Progression: Evidence for the Presence of a Disease Versus Native Clone Effect

Introduction Myelodysplastic syndrome (MDS) patients who are treated with azacitidine (AZA) may develop drug resistance in a number of different ways. Distinguishing the mechanisms underlying disease progression to leukemia while on AZA as opposed to clonal evolution without an increasing blast count is challenging due to the difficulty of studying MDS clones and their effect on non-diseased hematopoietic stem cells (HSCs). The application of a robust mathematical model of hematopoiesis to MDS patients allows for the calculation of kinetic parameters reflective of the function of the dominant hematopoietic clones, and infers the behaviour of both HSCs and MDS clones. We demonstrate the application of such a model applied to IPSS int-2/hi risk MDS patients treated with AZA, and show how different natural histories of disease can be explained by changes in model parameters over time. We also demonstrate how interactions between modeled HSCs and MDS clones can be inferred from the model. Methods A database of 97 IPSS int-2/hi risk MDS patients treated with AZA was previously constructed containing longitudinal peripheral blood count and laboratory data during the period 2008-2016, and was used for model fitting. Of these patients, 79 patients had sufficient data for modeling. A mathematical model of hematopoiesis was developed based on a formulation by Colijn and Mackey and modified to include a bone marrow blast compartment. Hematopoietic kinetic parameters were fit to de-identified patient laboratory data using a Kalman filter. The model data input was adjusted for red blood cell and platelet transfusion frequency and weighted so that parameter fits were made insensitive to periods of acute illness as identified from chart review and ancillary laboratory values. The resulting fit parameters represented a weighted average of disease and native HSCs contributions. Model parameters were evaluated with respect to time and sensitivity analysis was done identifying optimal correlation with the development of AZA resistance. A novel analysis was developed to determine if the contributions of the native and disease HSCs to peripheral blood counts are in proportion to their clonal burdens, or if the AZA-resistant phenotype reflected an additional effect of the MDS clones on the native HSCs. Results A schematic of the improved model of hematopoiesis adapted to MDS is shown along with the distribution of data collected over time (Fig 1A-B). The model fits for three representative patients are shown with different disease courses: AZA resistance with a rapidly rising blast count (patient 90), AZA resistance with a minimal rise in the blast count (patient 86), and AZA resistance with cytogenetic evolution without an increase in the blast count (patient 74). The model was fit to the longitudinal peripheral blood counts and bone marrow blast count data (Fig 2A-D). Development of AZA resistance in patient 74 was best correlated with a reduction in the average HSC self-renewal time (τS in Fig 2E), and this reduction was related to disease burden in a linear manner (Fig 2F, leftmost panel). Similarly, the development of AZA resistance in patient 86 was best correlated with an increase in the intrinsic threshold rate at which a stem cell differentiates (k0 in Fig 2E), and this increase was related to disease burden in a non-linear manner (Fig 2F, middle panel). For patient 90, the development of AZA resistance was best correlated with a decrease in the maximum rate of HSC differentiation (f0 in Fig 2E), and this decrease was related to disease burden in a non-linear manner (Fig 2F, rightmost panel). Discussion MDS patients in our cohort developed AZA resistance in distinct ways, and this correlated with changes in either HSC self-renewal time, differentiation threshold, or maximum differentiation rate. In the former case, the linearity in modeled HSC self-renewal time with respect to disease burden suggested this parameter change is accounted for by an expanding MDS clone. In the latter two cases, the mechanism of AZA resistance is hypothesized to be associated with an increased MDS clone threshold for differentiation as well as decreased maximum rate of HSC differentiation. The non-linearity of the association between these rate changes and disease burden suggests they were driven in large part by an external influence from the MDS clone on the HSCs. Further validation of these findings in a larger cohort of MDS patients is anticipated. Disclosures No relevant conflicts of interest to declare.

Mercury exposure to red-winged blackbirds (Agelaius phoeniceus) and dragonfly (Odonata: Aeshnidae) nymphs in Prairie Pothole wetlands

The Prairie Pothole Region (PPR) in the northern Great Plains is an area of ecological significance, serving as an important breeding site for avian wildlife. However, organisms feeding within the PPR may be at risk of mercury (Hg) exposure due to deposition of anthropogenic emissions and the high Hg methylation potential of PPR wetlands. We quantified Hg concentrations in red-winged blackbirds’ ( Agelaius phoeniceus (Linnaeus, 1766); RWBLs) blood, feathers, and eggs in the spring and summer breeding season and compared our values with those from RWBLs sampled from ecoregions across North America. Hg concentrations in whole water, aeshnid dragonfly nymphs, and RWBL tissues varied by wetland and were below those considered to elicit acute effects in wildlife, and egg total Hg (THg) concentrations were significantly related to spring whole water methylmercury concentrations. Only RWBL blood THg concentrations showed a clear increase in summer compared with spring, resulting in decoupling of summer blood and feather THg concentrations. Moreover, blood THg concentrations varied by ecoregion, with those impacted by an industrial point source exhibiting high Hg levels. Our study emphasizes that tissue renewal time as well as ecological factors such as competition and diet shifts are important considerations when using RWBLs to assess biological Hg exposure.

Analysis of Selected Reliability Indicators of Water Supply Network

The operation of the water supply network is related to ensuring the reliability of water supply to each customer. The reliability analysis of water supply can be based on reliability indicators of renewable objects such as water pipes. These indicators take into account the characteristics of the system and its components, by function or numerical characteristics. An example of reliability analysis for main and distribution pipes was made. The average renewal time, the average working time without failure and the reliability of network operation were determined.

Modelling of Environmental Parameters of a Harbor Basin in a Coastal Zone with a Seawall

Long straight seawalls along the coastal front are quite common, especially in cases of coastal cities. In this study in the middle of a coastal zone, a harbor basin in the form of an orthogonal area recessed to the waterfront is considered. A mole of variable length and position offers protection from waves. The renewal time of the waters and the self-purification capacity of the harbor under the influence of alongshore coastal currents of different intensity were examined. The effect of technical partial closing of the harbor’s entrance to the water renewal rate is examined in the present research. More specifically, the study was based on the use of a two dimensional, depth averaged hydrodynamic model which describes the water circulation along the coastal zone. For the solution of the equations of mass and momentum conservation, the method of finite differences was used. The adjustment and the validation of the reliability of the numerical model at a laboratory level were conducted in a recent research based on the use of PIV measurements which ensured a very good agreement between numerical and experimental results.

MORPHOLOGICAL MAPPING OF THE BOTTOM OF MESOLOGGI LAGOON WITH THE USE OF ASTRONAUT PHOTOGRAPHY AND GIS

Mesologi lagoon is a large and shallow environment with intense fish farming applications and the consequent enclosing of very large areas with fish fences and nets, which make field mapping almost impossible. Anthropogenic influence is eminent and a recent and updated morphological map was necessary. A mapping technique is presented based on the use of astronaut photography that is distributed freely by the Internet site of NASA. The digital photograph was geometrically corrected, visually, as semi transparent layer over a scanned map image by the use of PHOTOSHOP software. The areas of known depth were used to classify the depths of the lagoon with the PHOTOSHOP tool "replace color". An image therefore was produce with the depths classified as solid colors. This image was used as base map in MAPINFO, to produce a digital map in GIS environment, where all anthropogenic influence and depths (as depth ranges) are exist as separate layers and reveal the morphological background of the lagoon. The GIS map was used to calculate the water volume of the lagoon and the changes of the volume, as the sea level fluctuates with the tide. The depth-volume diagram was created and shows that during low water (-30cm) the volume is reduced by 43%, in contrast an increase of only 12% when sea level become 30cm higher. This is the result of the construction of peripheral embankments that restricts extension of the lagoon in high water. The implication of this situation is that the water renewal is restricted when sea level is kept high by a barometric low or an onshore wind, in contrast to very good renewal time when sea level is kept low by a barometric high.