Role of counterions in the adsorption and micellization behavior of 1:1 ionic surfactants at fluid interfaces─demonstrated by the standard amphiphile system of alkali perfluoro-n-octanoates

In our latest communication, we proved experimentally that the ionic surfactant’s surface excess is exclusively determined by the size of the hydrated counterion.[Lunkenheimer, Langmuir, 2017, 33, 10216−1022410.1021/acs.langmuir.7b00786]. However, at this stage of research, we were unable to decide whether this does only hold for the two or three lightest ions of lithium, sodium, and potassium, respectively. Alternatively, we could also consider the surface excess of the heavier hydrated alkali ions of potassium, rubidium, and cesium, having practically identical ion size, as being determined by the cross-sectional area of the related anionic extended chain residue. The latter assumption has represented state of art. Searching for reliable experimental results on the effect of the heavier counterions on the boundary layer, we have extended investigations to the amphiphiles’ solutions of concentrations above the critical concentration of micelle formation (cmc).We provided evidence that the super-micellar solutions’ equilibrium surface tension will remain constant provided the required conditions are followed. The related σcmccmccmc+ > Na+ > K+ > (NH4)+ > Rb+ > Cs+. Therefore, we have to extend our model of counterion effectiveness put forward in our previous communication. It represents a general principle of the counterion effect

The Effects of Indoor Environmental Exposures on Pediatric Asthma: A Discrete Event Simulation Model

Background: In the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date. Methods: We designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of $NO_2$ and $PM_{2.5}$, cockroach allergen, and dampness as a proxy for mold. Results: Model design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates. Conclusions: We describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma

Central and peripheral corneal thickness measurement with Orbscan II and topographical ultrasound pachymetry

PURPOSE: To compare thickness measurements of the central 6.0 mm of the cornea obtained with the Orbscan(R) II topography system and topographical ultrasound pachymetry. SETTING: School of Optometry, University of Santiago de Compostela, Galicia, Spain. METHODS: In 24 right eyes, pachymetric measurements were taken at the center and 1.2 mm and 3.0 mm on the superior and inferior hemimeridians. A 1-sample t test was applied to assess the significance of the relationship between Orbscan II and ultrasound methods. The relationship between the 2 was assessed by analyzing regression and plotting the differences against the mean corneal thickness. Orbscan II data were analyzed in 3 ways: (1) without the application of an acoustic equivalent correction factor; (2) with a correction factor of 0.92, as recommended by the manufacturer; (3) with correction using the equations derived in this study. The data were systematically compared with those of ultrasound pachymetry. RESULTS: Before the correction factor was applied, the Orbscan II overestimated the corneal thickness at all locations, with the mean difference (48.15 microm +/- 33.74 [SD]) significantly different from zero (P .05). CONCLUSIONS: The acoustic equivalent correction factor proposed by the manufacturer to obtain corneal thickness measurements with the Orbscan II compared to those from ultrasound pachymetry was not valid for all corneal topography positions. Orbscan II measurements agreed better with those of ultrasound pachymetry when equations for the central and each peripheral location across the topography were applied

Resource Utilization Reduction for Evaluation of Chest Pain in Pediatrics Using a Novel Standardized Clinical Assessment and Management Plan (SCAMP)

Background: Chest pain is a common reason for referral to pediatric cardiologists. Although pediatric chest pain is rarely attributable to serious cardiac pathology, extensive and costly evaluation is often performed. We have implemented a standardized approach to pediatric chest pain in our pediatric cardiology clinics as part of a broader quality improvement initiative termed Standardized Clinical Assessment and Management Plans (SCAMPs). In this study, we evaluate the impact of a SCAMP for chest pain on practice variation and resource utilization. Methods and results: We compared demographic variables, clinical characteristics, and cardiac testing in a historical cohort (n=406) of patients presenting to our outpatient division for initial evaluation of chest pain in the most recent pre-SCAMP calendar year (2009) to patients enrolled in the chest pain SCAMP (n=364). Demographic variables including age at presentation, sex, and clinical characteristics were similar between groups. Adherence to the SCAMP algorithm for echocardiography was 84%. Practice variation decreased significantly after implementation of the SCAMP (P<0.001). The number of exercise stress tests obtained was significantly lower in the SCAMP-enrolled patients compared with the historic cohort (∼3% of patients versus 29%, respectively; P<0.001). Similarly, there was a 66% decrease in utilization of Holter monitors and 75% decrease in the use of long-term event monitors after implementation of the chest pain SCAMP (P=0.003 and P<0.001, respectively). The number of echocardiograms obtained was similar between groups. Conclusions: Implementation of a SCAMP for evaluation of pediatric chest pain has lead to a decrease in practice variation and resource utilization

Using Inequality Measures to Incorporate Environmental Justice into Regulatory Analyses

Formally evaluating how specific policy measures influence environmental justice is challenging, especially in the context of regulatory analyses in which quantitative comparisons are the norm. However, there is a large literature on developing and applying quantitative measures of health inequality in other settings, and these measures may be applicable to environmental regulatory analyses. In this paper, we provide information to assist policy decision makers in determining the viability of using measures of health inequality in the context of environmental regulatory analyses. We conclude that quantification of the distribution of inequalities in health outcomes across social groups of concern, considering both within-group and between-group comparisons, would be consistent with both the structure of regulatory analysis and the core definition of environmental justice. Appropriate application of inequality indicators requires thorough characterization of the baseline distribution of exposures and risks, leveraging data generally available within regulatory analyses. Multiple inequality indicators may be applicable to regulatory analyses, and the choice among indicators should be based on explicit value judgments regarding the dimensions of environmental justice of greatest interest

Unique technique of surgery in an unusual variety of Scimitar syndrome: A Case Report

Scimitar syndrome is a rare congenital anomaly characterized by total or partial anomalous pulmonary venous drainage of the right lung to the inferior vena cava. We present a seven year old girl with a systolic murmur who was diagnosed as having a Scimitar syndrome with unusual drainage of the right pulmonary veins. The unique technique of surgery in this patient was appropriate to the unusual, previously not described anatomy

Radiographic lung disease and response of persistent pulmonary hypertension to mean airway pressure and alkalosis

Persistent pulmonary hypertension of the newborn (PPHN) is associated with multiple cardiopulmonary diseases. Therapy often includes hyperventilation/alkalosis despite little evidence as to its efficacy in diverse conditions. To determine (1) if part of the improvement of arterial oxygen tension (P ao 2 ) attributed to alkalosis is actually related to increased mean airway pressure (P aw ) and (2) if the presence of radiographic pulmonary disease predicts the response to alkalosis or mean airway pressure, we reviewed records of 19 newborns with well-documented PPHN. Arterial blood gases and corresponding ventilator settings were recorded during the first day of life. To adjust for lower F io 2 corrected P ao 2 (cP ao 2 ) was calculated when the F io 2 < 1.0, such that cP ao 2 = calculated arterial/alveolar oxygen ratio x (71 3 - P aco 2 /0.8). Regression equations were obtained and mean slopes of these were compared for P aw vs. cP ao 2 , and pH vs. cP ao 2 by one group t-tests (with assumed population slope of zero). There was no correlation between P aw and cP ao 2 (mean slope ± SD = −8.4 ± 30.8, P = 0.25), but there was a moderate correlation between p d and cP ao 2 (mean slope = 333.1 ± 480.5, P = 0.007). Patients were then classified by chest radiographs as having severe or minima/no lung disease. Relationships of P aw and pH to cP ao 2 were then re-examined. No correlation was present between P aw and cP ao 2 , in 11 patients with PPHN and severe radiographic disease (mean slope = −7.4 ± 26.97 P = 0.38) or in eight patients with PPHN and minima/no lung disease (mean slope = −9.8 2 37.5, P = 0.48). There was no correlation between pH and CP in patients with severe radiographic lung disease and PPHN (mean slope = 92.1 t 399.5, P 7 0.46), but patients with PPHN and minimal/no lung disease showed a strong correlation (mean slope = 664.5 ± 385.8, P = 0.002). We conclude that Paw (≤18 cm H 2 ,O) with conventional mechanical ventilation has no apparent effect on oxygenation in patients with PPHN regardless of lung disease; however, severe radiographic lung disease may be a predominant variable predicting a poor response to alkalosis. We speculate that different diseases cause pulmonary hypertension by different mechanisms. Pediatr Pulmonol. 1994; 17:239–245. © 1994 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38599/1/1950170407_ftp.pd

Pulmonary Arterial Stent Implantation in an Adult with Williams Syndrome

We report a 38-year-old patient who presented with pulmonary hypertension and right ventricular dysfunction due to pulmonary artery stenoses as a manifestation of Williams syndrome, mimicking chronic thromboembolic pulmonary hypertension. The patient was treated with balloon angioplasty and stent implantation. Short-term follow-up showed a good clinical result with excellent patency of the stents but early restenosis of the segments in which only balloon angioplasty was performed. These stenoses were subsequently also treated successfully by stent implantation. Stent patency was observed 3 years after the first procedure