Multi-scattering software part II: experimental validation for the light intensity distribution.

This article, Part II of an article series on GPU-accelerated Monte Carlo simulation of photon transport through turbid media, focuses on the validation of the online software Multi-Scattering. While Part I detailed the implementation of the computational model, simulated and experimental results are now compared for the distribution of the scattered light intensity. The scattering phantoms prepared here are aqueous dispersions of polystyrene microspheres of diameter D = 0.5, 2 and 5 µm and at various concentrations, resulting in optical depth ranging from OD = 1 to 17.5. The Lorenz-Mie scattering phase functions used in the simulations have been verified experimentally at low particle concentrations by analyzing the angular light intensity distribution at the Fourier plane of a collecting lens. The validation approach herein accounts for the specific light collection and image formation by the camera. The front and side surfaces of the medium are imaged and the corresponding light intensity distributions are compared qualitatively and quantitatively. It is concluded that the model enables reliable simulations over the tested parameters, offering predictive simulations of transmitted intensities with a mean relative error ≤~19% over the full range. The online software is available at: https://multi-scattering.com/.

High-Resolution Maps of Material Stocks in Buildings and Infrastructures in Austria and Germany.

The dynamics of societal material stocks such as buildings and infrastructures and their spatial patterns drive surging resource use and emissions. Two main types of data are currently used to map stocks, night-time lights (NTL) from Earth-observing (EO) satellites and cadastral information. We present an alternative approach for broad-scale material stock mapping based on freely available high-resolution EO imagery and OpenStreetMap data. Maps of built-up surface area, building height, and building types were derived from optical Sentinel-2 and radar Sentinel-1 satellite data to map patterns of material stocks for Austria and Germany. Using material intensity factors, we calculated the mass of different types of buildings and infrastructures, distinguishing eight types of materials, at 10 m spatial resolution. The total mass of buildings and infrastructures in 2018 amounted to ∼5 Gt in Austria and ∼38 Gt in Germany (AT: ∼540 t/cap, DE: ∼450 t/cap). Cross-checks with independent data sources at various scales suggested that the method may yield more complete results than other data sources but could not rule out possible overestimations. The method yields thematic differentiations not possible with NTL, avoids the use of costly cadastral data, and is suitable for mapping larger areas and tracing trends over time.

National-scale mapping of building height using Sentinel-1 and Sentinel-2 time series.

Urban areas and their vertical characteristics have a manifold and far-reaching impact on our environment. However, openly accessible information at high spatial resolution is still missing at large for complete countries or regions. In this study, we combined Sentinel-1A/B and Sentinel-2A/B time series to map building heights for entire Germany on a 10 m grid resolving built-up structures in rural and urban contexts. We utilized information from the spectral/polarization, temporal and spatial dimensions by combining band-wise temporal aggregation statistics with morphological metrics. We trained machine learning regression models with highly accurate building height information from several 3D building models. The novelty of this method lies in the very fine resolution yet large spatial extent to which it can be applied, as well as in the use of building shadows in optical imagery. Results indicate that both radar-only and optical-only models can be used to predict building height, but the synergistic combination of both data sources leads to superior results. When testing the model against independent datasets, very consistent performance was achieved (frequency-weighted RMSE of 2.9 m to 3.5 m), which suggests that the prediction of the most frequently occurring buildings was robust. The average building height varies considerably across Germany with lower buildings in Eastern and South-Eastern Germany and taller ones along the highly urbanized areas in Western Germany. We emphasize the straightforward applicability of this approach on the national scale. It mostly relies on freely available satellite imagery and open source software, which potentially permit frequent update cycles and cost-effective mapping that may be relevant for a plethora of different applications, e.g. physical analysis of structural features or mapping society's resource usage.

Fluoride Content in Asian Produced Green Teas.

BACKGROUND: This study determined the fluoride content of green tea from various parts of Asia, where green tea originates. METHODS: We brewed 2.5 g each of 4 types of green tea (from China, South Korea, Japan and Sri Lanka) using deionized water heated to boiling. Water was cooled to 71°C, then tea was steeped for 2 minutes. This process was repeated 20 times, thus providing 20 samples for each tea type. In addition, 20 control samples of deionized water were brewed to the same specifications. Samples were analyzed using a fluoride probe, and statistical power was calculated. RESULTS: The tea samples from different countries varied in the amount of fluoride they contained. The Chinese sample contained the most fluoride, while the Japanese sample contained the least. Means and interquartile ranges of fluoride concentration were calculated for each sample: Sri Lanka 3.58 ppm (0.1425), Chinese 6.83 ppm (0.140), South Korean 5.36 ppm (0.0975), Japanese 1.88 ppm (0.1375) and control 0.33 ppm (0.0078). CONCLUSION: The origin of tea and environmental factors, such as pollution, groundwater, air and the soil in which it was grown appear to directly affect the amount of fluoride that accumulates in the plants. Considering the fluoride content revealed by this study, green tea consumption habits should be taken into account when prescribing adjunct fluoride therapy as part of a preventative program for patient care.

Mapping urban-rural gradients of settlements and vegetation at national scale using Sentinel-2 spectral-temporal metrics and regression-based unmixing with synthetic training data.

The increasing impact of humans on land and ongoing global population growth requires an improved understanding of land cover (LC) and land use (LU) processes related to settlements. The heterogeneity of built-up areas and infrastructures as well as the importance of not only mapping, but also characterizing anthropogenic structures suggests using a sub-pixel mapping approach for analysing related LC from space. We implement a regression-based unmixing approach for mapping built-up surfaces and infrastructure, woody vegetation and non-woody vegetation for all of Germany and Austria at 10 m resolution to demonstrate the potential of sub-pixel mapping. We map LC fractions for one point in time, using all available Sentinel-2 data from 2017 and 2018 (<70% cloud cover). We combine the concept of synthetically mixed training data with statistical aggregations from spectral-temporal metrics (STM) derived from Sentinel-2 reflectance time series. We specifically examine how STM can be used for creating synthetically mixed training data. STM are known to facilitate large area mapping by being largely independent of image acquisition dates and inherently incorporate phenological information. Vegetation is an important part of settlements and time series information supports its mapping. Synthetically mixed training data facilitates a streamlined training by using pure reference spectra to generate artificial mixtures as input to regression modelling of LC fractions in mixed pixels. We here show how combining both offers great potential for wall-to-wall LC fraction mapping. We further investigate the positive effect of STM on map results by comparing the performance of different subsets of STM combinations. Our results indicate that many STM combinations containing spectral variability and vegetation indices provide suitable input to creating synthetic training data for regression-based fraction mapping. Results for built-up surfaces and infrastructure (MAE 0.13/RMSE 0.18 at 20 m resolution), woody vegetation (0.18, 0.22) and non-woody vegetation (0.14, 0.19) are highly consistent across Germany and Austria. Only a few surface types were not accurately predicted in our nation-wide mapping. Further research is required to optimize mapping of temporally invariant bare soil and rock surfaces that show spectral similarity to built-up surfaces and infrastructure. The proposed methodology combines benefits of both regression-based modelling with synthetically mixed training data and STM, and thus facilitates mapping of LC fractions on a national scale and at high resolution. Such information will allow to better characterize settlements and identifying processes such as densification that are best represented by continuous LC mapping.

High-resolution data and maps of material stock, population, and employment in Austria from 1985 to 2018.

High-resolution maps of material stocks in buildings and infrastructures are of key importance for studies of societal resource use (social metabolism, circular economy, secondary resource potentials) as well as for transport studies and land system science. So far, such maps were only available for specific years but not in time series. Even for single years, data covering entire countries with high resolution, or using remote-sensing data are rare. Instead, they often have local extent (e.g., [1]), are lower resolution (e.g., [2]), or are based on other geospatial data (e.g., [3]). We here present data on the material stocks in three types of buildings (commercial and industrial, single- and multifamily houses) and three types of infrastructures (roads, railways, other infrastructures) for a 33-year time series for Austria at a spatial resolution of 30 m. The article also presents data on population and employment in Austria for the same time period, at the same spatial resolution. Data were derived with the same method applied in a recent study for Germany [4].

Unveiling patterns in human dominated landscapes through mapping the mass of US built structures.

Built structures increasingly dominate the Earth's landscapes; their surging mass is currently overtaking global biomass. We here assess built structures in the conterminous US by quantifying the mass of 14 stock-building materials in eight building types and nine types of mobility infrastructures. Our high-resolution maps reveal that built structures have become 2.6 times heavier than all plant biomass across the country and that most inhabited areas are mass-dominated by buildings or infrastructure. We analyze determinants of the material intensity and show that densely built settlements have substantially lower per-capita material stocks, while highest intensities are found in sparsely populated regions due to ubiquitous infrastructures. Out-migration aggravates already high intensities in rural areas as people leave while built structures remain - highlighting that quantifying the distribution of built-up mass at high resolution is an essential contribution to understanding the biophysical basis of societies, and to inform strategies to design more resource-efficient settlements and a sustainable circular economy.

Neurologic complications of bariatric surgery: involvement of central, peripheral, and enteric nervous systems.

Approximately one in three Americans is obese. Current society guidelines recommend bariatric surgery after conservative measures at weight loss have failed. The frequency of bariatric surgeries has increased significantly over the past decade. While considered both safe and effective, bariatric surgery presents a distinct set of risks. This review focuses on the neurological complications of bariatric surgery. Injuries have been reported at all levels of the nervous system, including the central, peripheral, and enteric nervous system. Injury can be classified according to time of presentation and location. The two main mechanisms of nerve injury are from mechanical injury or as a consequence of malnutrition. Encephalopathy, peripheral neuropathies, myelopathies, and radiculoneuropathies have all been reported. Mechanical injuries likely occur from mechanical compression. Malnutrition injuries result from multi-micronutrient deficiencies. The most likely candidates are vitamin B12, folate, zinc, thiamin, copper, vitamin A, and vitamin E deficiencies.

High contrast, isotropic, and uniform 3D-imaging of centimeter-scale scattering samples using structured illumination light-sheet microscopy with axial sweeping.

Light-sheet fluorescent microscopy (LSFM) has, in recent years, allowed for rapid 3D-imaging of cleared biomedical samples at larger and larger scale. However, even in cleared samples, multiple light scattering often degrades the imaging contrast and widens the optical sectioning. Accumulation of scattering intensifies these negative effects as light propagates inside the tissue, which accentuates the issues when imaging large samples. With axially swept light-sheet microscopy (ASLM), centimeter-scale samples can be scanned with a uniform micrometric optical sectioning. But to fully utilize these benefits for 3D-imaging in biomedical tissue samples, suppression of scattered light is needed. Here, we address this by merging ASLM with light-sheet based structured illumination into Structured Illumination Light-sheet Microscopy with Axial Sweeping (SILMAS). The SILMAS method thus enables high-contrast imaging, isotropic micrometric resolution and uniform optical sectioning in centimeter-scale scattering samples, creating isotropic 3D-volumes of e.g., whole mouse brains without the need for any computation-heavy post-processing. We demonstrate the effectiveness of the approach in agarose gel phantoms with fluorescent beads, and in an PFF injected alpha-synuclein transgenic mouse model tagged with a green fluorescent protein (SynGFP). SILMAS imaging is compared to standard ASLM imaging on the same samples and using the same optical setup, and is shown to increase contrast by as much as 370% and reduce widening of optical sectioning by 74%. With these results, we show that SILMAS improves upon the performance of current state-of-the-art light-sheet microscopes for large and imperfectly cleared tissue samples and is a valuable addition to the LSFM family.

The optimal lipid formulation in enteral feeding in critical illness: clinical update and review of the literature.

Suitable and timely early enteral nutrition is paramount to providing optimal patient care for the critically ill. Lipids serve many essential roles throughout the human body, and are important components of most enteral formulations. This paper reviews lipid structure, function, and optimal utility for this macronutrient in enteral feeds. The use of omega-3 fatty acids has become common in critical care formulations, and their clinical efficacy is outlined separately. Available evidence is reviewed, and future directions are discussed.

Current perception of nutrition education in U.S. medical schools.

Historically, physicians have perceived the quality of nutrition training during medical school as inadequate. A literature review suggests that this perception has not significantly changed since the 1950s. Many schools have worked to create clinical nutrition curricula for use during medical school. Interestingly, data suggest that medical students' perception of the importance of clinical nutrition can decrease during medical school. Recent data support the importance of targeted nutritional therapy to reduce morbidity and mortality, yet the number of physicians interested in nutrition appears to be declining, and fewer hours of nutrition training are occurring in medical school. One possible solution to improve both training and awareness of the problem is to implement a certification program for both students and preceptors modeled after the Cardiac Life Support training offered by the American Heart Association.

Gridded population mapping for Germany based on building density, height and type from Earth Observation data using census disaggregation and bottom-up estimates.

Gridded population data is widely used to map fine scale population patterns and dynamics to understand associated human-environmental processes for global change research, disaster risk assessment and other domains. This study mapped gridded population across Germany using weighting layers from building density, building height (both from previous studies) and building type datasets, all created from freely available, temporally and globally consistent Copernicus Sentinel-1 and Sentinel-2 data. We first produced and validated a nation-wide dataset of predominant residential and non-residential building types. We then examined the impact of different weighting layers from density, type and height on top-down dasymetric mapping quality across scales. We finally performed a nation-wide bottom-up population estimate based on the three datasets. We found that integrating building types into dasymetric mapping is helpful at fine scale, as population is not redistributed to non-residential areas. Building density improved the overall quality of population estimates at all scales compared to using a binary building layer. Most importantly, we found that the combined use of density and height, i.e. volume, considerably increased mapping quality in general and with regard to regional discrepancy by largely eliminating systematic underestimation in dense agglomerations and overestimation in rural areas. We also found that building density, type and volume, together with living floor area per capita, are suitable to produce accurate large-area bottom-up population estimates.

When to consider endoscopic ablation therapy for Barrett's esophagus.

PURPOSE OF REVIEW: To evaluate timing and patient selection for endoscopic ablative therapy in Barrett's esophagus. RECENT FINDINGS: There has been an explosion in the literature describing ablative therapy in Barrett's esophagus. Most recent data describe radiofrequency ablation (RFA), but other data pertain to photodynamic therapy (PDT) and other modalities. Most studies are cohort or case series. Reversion to squamous epithelium is the most common primary outcome. Cancer incidence data are scarce. RFA appears well tolerated. The main side-effect is chest pain, which can be managed with oral analgesics. Stricture occurs in 0-8% and is amenable to endoscopic dilatation. Infrequent side-effects include bleeding and perforation. Complete reversion to squamous epithelium occurs in more than 90% of nondysplastic and low-grade dysplasia and more than 80% in high-grade dysplasia patients, and the treatment appears durable for at least 2-5 years of available follow-up. Treatment of low-grade or nondysplastic disease may be cost-effective. PDT data suggest that all-cause mortality is similar to surgery for dysplastic Barrett's esophagus. The stricture rate appears higher, and rates of complete reversion to neosquamous epithelium are lower than that of RFA, although definitive comparisons are lacking. SUMMARY: The excellent efficacy, side-effect profile, and cost-effectiveness appear to make RFA the intervention of choice in cases of high-grade dysplasia. RFA for low-grade dysplasia may be of value in young patients and/or those with long segment or multifocal disease. Treatment of nondysplastic Barrett's esophagus is of uncertain value. PDT appears to have a higher stricture rate and to be more expensive than RFA.

Single-balloon enteroscopy: results from an initial experience at a U.S. tertiary-care center.

BACKGROUND: Single-balloon enteroscopy (SBE) is a novel, deep-enteroscopy modality for diagnosis and treatment of disorders of the small bowel. OBJECTIVE: The aim of the study was to examine the performance, yield, and safety of SBE in the initial experience at a tertiary-care center. DESIGN: Retrospective analysis of all SBEs during a 10-month period in 2008. Data were extracted from electronic clinical and endoscopy records. SETTING: U.S. tertiary-care center. PATIENTS: All patients referred to our center for SBE during the study period were included in the current analysis. INTERVENTION: SBE. MAIN OUTCOME MEASUREMENTS: Anterograde SBE procedure time, diagnostic yield, and complications. RESULTS: Thirty-eight anterograde SBEs were performed. The mean patient age was 62 years (42% female). Patients were referred for GI bleeding (97%), Crohn's disease, suspected polyps or neoplasia, and abnormal capsule endoscopy results. The mean (+/- SD) procedure time was 49 +/- 19 minutes. The estimated depth of insertion was proximal jejunum (34%), mid-jejunum (45%), and distal jejunum (21%). The SBE diagnostic yield was 47%, with significant findings in 18 patients. Findings included angiectasias, bleeding, abnormal mucosa, ulceration, polyps, and a foreign body. The therapeutic yield was 42%, with lesion ablation performed in 24% of cases. Diagnostic biopsies were performed in 24% of cases and tattooing in 52%. There were no significant complications. LIMITATIONS: Single-center, retrospective study. CONCLUSION: Single-balloon enteroscopy appears to be a safe and efficient method for examination of the mid-small bowel. The significant therapeutic yield (42%) suggests that comparative studies with double-balloon and spiral enteroscopy are warranted.

Atmospheric Correction Inter-comparison eXercise.

The Atmospheric Correction Inter-comparison eXercise (ACIX) is an international initiative with the aim to analyse the Surface Reflectance (SR) products of various state-of-the-art atmospheric correction (AC) processors. The Aerosol Optical Thickness (AOT) and Water Vapour (WV) are also examined in ACIX as additional outputs of an AC processing. In this paper, the general ACIX framework is discussed; special mention is made of the motivation to initiate this challenge, the inter-comparison protocol and the principal results. ACIX is free and open and every developer was welcome to participate. Eventually, 12 participants applied their approaches to various Landsat-8 and Sentinel-2 image datasets acquired over sites around the world. The current results diverge depending on the sensors, products and sites, indicating their strengths and weaknesses. Indeed, this first implementation of processor inter-comparison was proven to be a good lesson for the developers to learn the advantages and limitations of their approaches. Various algorithm improvements are expected, if not already implemented, and the enhanced performances are yet to be investigated in future ACIX experiments.

Evaluating the trade-off between food and timber resulting from the conversion of Miombo forests to agricultural land in Angola using multi-temporal Landsat data.

The repopulation of abandoned areas in Angola after 27years of civil war led to a fast and extensive expansion of agricultural fields to meet the rising food demand. Yet, the increase in crop production at the expense of natural resources carries an inherent potential for conflicts since the demand for timber and wood extraction are also supposed to rise. We use the concept of ecosystem services to evaluate the trade-off between food and woody biomass. Our study area is located in central Angola, in the highlands of the upper Okavango catchment. We used Landsat data (spatial resolution: 30×30m) with a bi-temporal and multi-seasonal change detection approach for five time steps between 1989 and 2013 to estimate the conversion area from woodland to agriculture. Overall accuracy is 95%, user's accuracy varies from 89-95% and producer's accuracy ranges between 92-99%. To quantify the trade-off between woody biomass and the amount of food, this information was combined with indicator values and we furthermore assessed biomass regrowth on fallows. Our results reveal a constant rise in agricultural expansion from 1989-2013 with the mean annual deforestation rate increasing from roughly 5300ha up to about 12,000ha. Overall, 5.6% of the forested areas were converted to agriculture, whereas the FAO states a national deforestation rate for Angola of 5% from 1990-2010 (FAO, 2010). In the last time step 961,000t per year of woodland were cleared to potentially produce 1240t per year of maize. Current global agro-economical projections forecast increasing pressure on tropical dry forests from large-scale agriculture schemes (Gasparri et al., 2015; Searchinger and Heimlich, 2015). Our study underlines the importance of considering subsistence-related change processes, which may contribute significantly to negative effects associated with deforestation and degradation of these forest ecosystems.

Cross-Sectional Study of U.S. Interns' Perceptions of Clinical Nutrition Education.

Background Medical students have historically perceived a lack of training in clinical nutrition. Rapid advances in medical science have compelled significant changes in medical education pedagogy. It is unclear what effect this has had on student's perceptions. Objective To assess interns' perception of clinical nutrition education during medical school. Design A cross-sectional survey of medical, surgical, and obstetric interns from 6 academic hospitals across the United States during the middle of their first year in November of 2010 (n = 289). Bivariate analysis and logistic regression was used to describe interns' perceptions and evaluate for factors that determined these perceptions. Results A total of 122 interns responded to the survey, for a response rate of 42%. These interns represented 72 different medical schools. Only 29% of interns reported they had been sufficiently trained in nutrition. On average, interns who reported being prepared reported a mean of 4 ± 3.4 weeks of training during medical school, while unprepared interns reported a mean of 2 ± 2.6 weeks of training (P = .02). Interns with prior graduate training in nutrition (n = 18) almost exclusively reported that medical school training was insufficient (94%, P = .02). After adjusting for age, gender, internship, undergraduate training, and being a foreign graduate, only the number of weeks of training remained significantly associated with perceived preparation (P = .03). Conclusion Most interns in medicine, surgery, and obstetrics feel unprepared to handle cases requiring knowledge of clinical nutrition. Interns feel that medical school is not adequately preparing them for the needs of clinical practice.

Percent Body Fat Measured by Bioelectrical Impedance is Not Associated with Colorectal Adenoma Status.

BACKGROUND: Obesity is a risk factor for colorectal neoplasia. Bioelectrical impedance analysis (BIA) is a novel and convenient method to measure body fat mass. The correlation between BIA and adenoma risk is unknown. AIMS: To conduct a cross-sectional study to evaluate BIA and other measures of obesity as risk factors for adenomas. METHODS: Participants underwent screening colonoscopy between 2006 and 2008. Waist-hip ratio (WHR) and body mass index (BMI) were measured. Percent body fat was calculated by BIA using a proprietary scale. Physical activity and other risk factors were assessed by telephone interview. RESULTS: 255 patients with adenomas and 679 adenoma-free subjects were included. Increased age, male sex, and decreased physical activity were associated with adenoma prevalence. In multivariate analysis, WHR and BMI were independently associated with adenoma prevalence. Patients in the highest tertile of WHR had an OR of 2.0 (95% CI 1.2-3.2) compared to the lowest tertile. Obese white patients had significantly increased odds of having adenomas (OR 2.0 (95% CI 1.3, 3.2)) compared to whites with a normal BMI. Percent body fat measured by BIA was not associated with adenoma status: patients in the highest tertile of percent body fat had an OR of 1.0 (95% CI 0.7-1.6) compared to patients with the lowest tertile. CONCLUSIONS: Percent body fat calculated by BIA was not associated with adenoma prevalence. Although BIA is a quick and convenient measure of adiposity, it is not predictive of adenoma risk perhaps because it measures the amount of fat but not the distribution.