In-line monitoring of polymer nanoparticle growth during synthesis in concentrated systems by photon density wave spectroscopy

Photon Density Wave (PDW) spectroscopy [1-4] determines the absolute optical properties of highly turbid liquid dispersions without a need for prior method calibration. As parameters, the absorption coefficient ma and the reduced scattering coefficient ms’ are obtained. Based on Mie theory and theories for dependent light scattering, the reduced scattering coefficient is linked to the particle size of the suspended particles, allowing for dilution-free particle sizing in size regimes of approx. 50 nm to 500 µm. Currently, PDW spectroscopy provides a time resolution of approx. 2 min-1 and can be operated with fiber-optical process probes [5], thus it allows for in-line particle size measurements during polymerization processes. Here, PDW spectroscopy was applied to investigate the growth of polymer nanoparticles in-line during their synthesis. Examples cover polymerization of styrene at 20 wt%, semi-batch polymerization of vinyl acetate up to solid fractions of 50 wt%, and starved feed copolymerization of acrylate-based monomers [6] up to 40 wt%. For example, in the case of the synthesis of polyvinyl acetate, it could be observed in-line that the growth of the polymer nanoparticles only commenced after a significant amount of monomer had been fed into the reactor (approx. 20 wt%), thus indicating that during the first hour after polymerization start mainly particle nucleation occurred. The results obtained with respect to particle size agreed well with off-line dynamic and static light scattering reference experiments, which required sampling and sample dilution. By the use of multiple laser wavelengths for PDW spectroscopy, an estimation of the particle size distribution during synthesis can be obtained as well [2]. In the case of polyvinyl acetate, the findings indicate an increasing particle size distribution width during its synthesis. Based on the estimation of the particle size distribution, particle numbers and particle growth rates can be calculated, thus providing access for an increased process understanding and finally an approach for real-time process control during synthesis of polymer nanoparticles in concentrated dispersions. [1] Bressel L., Hass R., Reich O., Particle sizing in highly turbid dispersions by photon density wave spectroscopy, J. Quant. Spectrosc. Radiat. Transf. 126:122-129 (2013). [2] Hass R., Münzberg M., Bressel L., Reich O., Industrial applications of Photon Density Wave spectroscopy for in-line particle sizing, Appl. Opt. 52:1423-1431 (2013). [3] Fishkin J.B., Fantini S., van de Ven M.J., Gratton E., Gigahertz photon density waves in a turbid medium: Theory and experiments, Phys. Rev. E 53:2307-2319 (1996). [4] Richter S.M., Shinde R.R., Balgi G.V., Sevick-Muraca E.M., Particle sizing using frequency domain photon migration, Part. Part. Syst. Charact. 15:9-15. (1998). [5] Hass R., Munzke D., Vargas Ruiz S., Tippmann J., Reich O., Optical monitoring of chemical processes in turbid biogenic liquid dispersions by photon density wave spectroscopy, Anal. Bioanal. Chem. 407:2791-2802 (2015). [6] Hass R., Reich O., Photon Density Wave spectroscopy for dilution-free sizing of highly concentrated nanoparticles during starved-feed polymerization, ChemPhysChem 12:2572-2575 (2011)

Perinatal mental disorders in Switzerland : prevalence estimates and use of mental-health services

Background: Perinatal mental disorders (PMDs) are the most common complication of pregnancy and the first postpartum year. Since PMD prevalence and use of mental-health services by perinatal women in Switzerland are unknown, we analysed existing health statistics. Methods: We used statistics from a large health insurance company, hospitals and freelance midwives. We assessed the annual rates of mental healthcare use in perinatal women (n = 13 969). We ascertained the annual rates of PMD treatment in obstetric inpatients (n = 89 699), and annual rates of PMD records by freelance midwives (n = 57 951). In 15 104 women who gave birth in 2012 or 2013, we assessed use of mental-healthcare before and during pregnancy, and in the postpartum year. For the same sample, we determined proportions of medication and consultation treatments. We used multiple regression analysis to estimate the influence of PMD on overall healthcare costs of mandatory health insurance. Results: The annual rate of mental-healthcare use by perinatal women was 16.7%. The annual rate of PMD treatment in obstetric inpatients was 1.1%. The annual rate of PMD records in the midwifery care setting was 2.9%. Women with PMD use mental health services mainly in non-obstetric outpatient settings. Medication was the most frequent treatment. Primary care providers and mental health specialists contributed almost equally to consultation treatments. PMD during pregnancy raised overall costs of healthcare in the postpartum year by 1214 Swiss francs. Conclusions: Health-system research and perinatal healthcare should take into consideration the high prevalence of PMD. Real PMD prevalence may be even higher than our data suggest and could be assessed with a survey using our model of PMD prevalence

An empirical investigation of the efficiency effects of integrated care models in Switzerland

<p><strong>Introduction:</strong> This study investigates the efficiency gains of integrated care models in Switzerland, since these models are regarded as cost containment options in national social health insurance. These plans generate much lower average health care expenditure than the basic insurance plan. The question is, however, to what extent these total savings are due to the effects of selection and efficiency.</p><p><strong>Methods:</strong> The empirical analysis is based on data from 399,274 Swiss residents that constantly had compulsory health insurance with the Helsana Group, the largest health insurer in Switzerland, covering the years 2006 to 2009. In order to evaluate the efficiency of the different integrated care models, we apply an econometric approach with a mixed-effects model.</p><p><strong>Results:</strong> Our estimations indicate that the efficiency effects of integrated care models on health care expenditure are significant. However, the different insurance plans vary, revealing the following efficiency gains per model: contracted capitated model 21.2%, contracted non-capitated model 15.5% and telemedicine model 3.7%. The remaining 8.5%, 5.6% and 22.5% respectively of the variation in total health care expenditure can be attributed to the effects of selection.</p><p><strong>Conclusions:</strong> Integrated care models have the potential to improve care for patients with chronic diseases and concurrently have a positive impact on health care expenditure. We suggest policy makers improve the incentives for patients with chronic diseases within the existing regulations providing further potential for cost-efficiency of medical care.</p

Does coordinated postpartum care influence costs?

Questions under study: To investigate changes to health insurance costs for post-discharge postpartum care after the introduction of a midwife-led coordinated care model. Methods: The study included mothers and their newborns insured by the Helsana health insurance group in Switzerland and who delivered between January 2012 and May 2013 in the canton of Basel Stadt (BS) (intervention canton). We compared monthly post-discharge costs before the launch of a coordinated postpartum care model (control phase, n = 144) to those after its introduction (intervention phase, n = 92). Costs in the intervention canton were also compared to those in five control cantons without a coordinated postpartum care model (cross-sectional control group: n = 7, 767). Results: The average monthly post-discharge costs for mothers remained unchanged in the seven months following the introduction of a coordinated postpartum care model, despite a higher use of midwife services (increasing from 72% to 80%). Likewise, monthly costs did not differ between the intervention canton and five control cantons. In multivariate analyses, the ambulatory costs for mothers were not associated with the post-intervention phase. Cross-sectionally, however, they were positively associated with midwifery use. For children, costs in the post-intervention phase were lower in the first month after hospital discharge compared to the pre-intervention phase (difference of –114 CHF [95%CI –202 CHF to –27 CHF]), yet no differences were seen in the cross-sectional comparison. Conclusions: The introduction of a coordinated postpartum care model was associated with decreased costs for neonates in the first month after hospital discharge. Despite increased midwifery use, costs for mothers remained unchanged

Epidemiology and costs of multiple sclerosis in Switzerland : an analysis of health-care claims data, 2011–2015

Background: Medical therapy for multiple sclerosis (MS) is expensive. Quantifying the burden of MS is fundamental for health-care planning and the allocation of resources for the management of MS. This study provides current national estimates of prevalence, incidence, mortality, and costs of MS in Switzerland using claims data between 2011 and 2015. Methods: We analyzed health insurance claims of adult persons enrolled with a large health insurance group covering about 13% of the Swiss population between 2011 and 2015. The identification of patients with MS was based on prescription data of MS-specific medication using the Anatomical Therapeutic Chemical Classification system as proxy for clinical diagnosis. We estimated prevalence, mortality, and costs of basic health insurance between 2011 and 2015. Furthermore, incidence of MS was calculated for 2015. All results were weighted with census data to achieve an extrapolation to the Swiss general population level. Cost of illness was estimated as direct medical cost from the perspective of a Swiss health insurance using multivariate linear regression analysis. Results: Of the 943,639 subjects in the year 2015, 1,606 were identified as MS patients resulting in a prevalence of 190 per 100,000 (95% CI: 180-190 per 100,000). Incidence was 16 per 100,000 (95% CI: 13-19 per 100,000). According to regression analysis, the total cost of illness for basic mandatory health insurance was 26,710 Swiss Francs (CHF) (95% CI: 26,100-27,300) per person per year with the cost of medication being almost identical 26,960 CHF (95% CI: 26,170-27,800). Conclusions: MS affects 10,000–15,000 persons in Switzerland, and the prevalence has increased over the last 22 years. These persons have high need and demand for health care. High costs are primarily due to expenses for medication. Given the imbalance of MS medication therapy from the perspective of basic health insurance on the disposable resources, it is crucial to increase transparency related to the volume, type, and allocation of expenses

Exciton-phonon coupling in individual GaAs nanowires studied using resonant Raman spectroscopy

The Fröhlich coupling strength of individual GaAs nanowires is investigated by resonant micro-Raman spectroscopy measurements near the direct bandgap E[subscript g]2. Large 2LO/1LO intensities up to 5.7 are observed in an individual GaAs nanowire. A 2LO resonance profile of the GaAs nanowire agrees well with a two-phonon-scattering model, suggesting excitonic scattering. These results advance the understanding of electron-phonon coupling and exciton scattering in quasi-one-dimensional systems and in GaAs at E[subscript g], allowing for the development and optimization of nanowire optoelectronic devices

Quality of life data from EQ-5D for evidence-based health service practice in dialysis care

Hemodialysis (HD) and peritoneal dialysis (PD) are therapeutic options for patients with end-stage-renal-disease (ESRD), if transplantation is not available. Mortality rates for HD and PD are similar, while PD is generally the less costly alternative. Percentage of HD and PD shows considerable variability between high income countries (for PD from 5-7% in Germany and Switzerland up to 19- 24% in the UK and Scandinavia). Patient reported outcomes, such as quality of life (QOL), can provide complementary evidence for planning of patient oriented dialysis services. Profile instruments (e.g. SF36, KDQOL) show no consistent QOL differences between HD and PD. However, single index preference-based QOL measures (such as EQ5D), may add new information and are useful for later health economic evaluations. We aimed to collect current evidence for QOL of ESRD patients as measured with EQ-5D

Randomised maximum likelihood based posterior sampling

Minimization of a stochastic cost function is commonly used for approximate sampling in high-dimensional Bayesian inverse problems with Gaussian prior distributions and multimodal posterior distributions. The density of the samples generated by minimization is not the desired target density, unless the observation operator is linear, but the distribution of samples is useful as a proposal density for importance sampling or for Markov chain Monte Carlo methods. In this paper, we focus on applications to sampling from multimodal posterior distributions in high dimensions. We first show that sampling from multimodal distributions is improved by computing all critical points instead of only minimizers of the objective function. For applications to high-dimensional geoscience problems, we demonstrate an efficient approximate weighting that uses a low-rank Gauss-Newton approximation of the determinant of the Jacobian. The method is applied to two toy problems with known posterior distributions and a Darcy flow problem with multiple modes in the posterior