bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and antiplasmodial activity of 3',4'‐dihydro‐1'H‐spiro(indoline‐3,2'‐quinolin)‐2‐ones
Authors: Mathebula Bakolise , Butsi Kamogelo Rosinah , van Zyl Robyn Lynne , Jansen van Vuuren Natasha Colleen , Hoppe Heinrich Carl , Michael Joseph Philip , de Koning Charles Bernard , Rousseau Amanda Louise 
Published: July 2019

AbstractA series of 3',4'‐dihydro‐1'H‐spiro(indoline‐3,2'‐quinolin)‐2‐ones were prepared by the inverse‐electron‐demand aza‐Diels–Alder reaction (Povarov reaction) of imines derived from isatin and substituted anilines, and the electron‐rich alkenes trans‐isoeugenol and 3,4‐dihydro‐2H‐pyran. These compounds were assessed for in vitro antiplasmodial activity against drug‐sensitive and drug‐resistant forms of the P. falciparum parasite. Three compounds derived from 3,4‐dihydro‐2H‐pyran and four compounds derived from trans‐isoeugenol showed antiplasmodial activity in the low micromolar range against the drug‐resistant FCR‐3 strain (1.52–4.20 µM). Only compounds derived from trans‐isoeugenol showed antiplasmodial activity against the drug‐sensitive 3D7 strain (1.31–1.80 µM).
Supporting unaccompanied asylum‐seeking young people: The experience of foster care
Authors: Wade Jim 
Published: July 2019

AbstractAlthough research on the experiences of unaccompanied asylum‐seeking young people in the UK has grown steadily in recent years, their experience of fostering and of the role played by foster carers in helping their adjustment have been neglected. This paper reports findings from the first UK study into these experiences, describing issues arising from initial assessment and preparation for fostering and the ways in which young people and foster carers adjusted to their lives together. It assesses the progress made by young people during placement, the strategies that appeared helpful to relationship building, and the extent to which young people had become integrated within the wider network of family relationships. Given that most young people first arrive as teenagers, it also considers the ways in which foster carers and social workers helped young people prepare for adult life in the context of uncertainties arising from the asylum process.
Could I do something like that? Recruiting and training foster carers for teenagers “at risk” of or experiencing child sexual exploitation
Authors: Shuker Lucie , Pearce Jenny 
Published: July 2019

AbstractChild sexual exploitation (CSE) is a category of child abuse that was historically created to recognize the victimhood of children and young people, illuminating the ways that their evolving capacity to consent to sex is manipulated and undermined. Using evidence from the evaluation of specialist foster care provision and a CSE training course for foster carers, this paper considers how training might be used to widen the pool of potential foster carers for children affected by CSE and identifies qualities displayed by effective carers. It argues that improving the recruitment of foster carers can create safer home environments for teenagers at risk of or experiencing sexual exploitation and reduce the risk of further harm and that informed and effective foster care provision is crucial to prevent both the sexual exploitation of looked‐after teenagers and placement breakdowns that can ultimately increase risk.
Microfacet Model Regularization for Robust Light Transport
Authors: Jendersie Johannes , Grosch Thorsten 
Published: July 2019

AbstractToday, Monte Carlo light transport algorithms are used in many applications to render realistic images. Depending on the complexity of the used methods, several light effects can or cannot be found by the sampling process. Especially, specular and smooth glossy surfaces often lead to high noise and missing light effects.Path space regularization provides a solution, improving any sampling algorithm, by modifying the material evaluation code. Previously, Kaplanyan and Dachsbacher [KD13] introduced the concept for pure specular interactions. We extend this idea to the commonly used microfacet models by manipulating the roughness parameter prior to the evaluation. We also show that this kind of regularization requires a change in the MIS weight computation and provide the solution. Finally, we propose two heuristics to adaptively reduce the introduced bias.Using our method, many complex light effects are reproduced and the fidelity of smooth objects is increased. Additionally, if a path was sampleable before, the variance is partially reduced.
Ray Classification for Accelerated BVH Traversal
Authors: Hendrich J. , Pospíšil A. , Meister D. , Bittner J. 
Published: July 2019

AbstractFor ray tracing based methods, traversing a hierarchical acceleration data structure takes up a substantial portion of the total rendering time. We propose an additional data structure which cuts off large parts of the hierarchical traversal. We use the idea of ray classification combined with the hierarchical scene representation provided by a bounding volume hierarchy. We precompute short arrays of indices to subtrees inside the hierarchy and use them to initiate the traversal for a given ray class. This arrangement is compact enough to be cache‐friendly, preventing the method from negating its traversal gains by excessive memory traffic. The method is easy to use with existing renderers which we demonstrate by integrating it to the PBRT renderer. The proposed technique reduces the number of traversal steps by 42% on average, saving around 15% of time of finding ray‐scene intersection on average.
Real‐time Image‐based Lighting of Microfacet BRDFs with Varying Iridescence
Authors: Kneiphof Tom , Golla Tim , Klein Reinhard 
Published: July 2019

AbstractIridescence is a natural phenomenon that is perceived as gradual color changes, depending on the view and illumination direction. Prominent examples are the colors seen in oil films and soap bubbles. Unfortunately, iridescent effects are particularly difficult to recreate in real‐time computer graphics. We present a high‐quality real‐time method for rendering iridescent effects under image‐based lighting. Previous methods model dielectric thin‐films of varying thickness on top of an arbitrary micro‐facet model with a conducting or dielectric base material, and evaluate the resulting reflectance term, responsible for the iridescent effects, only for a single direction when using real‐time image‐based lighting. This leads to bright halos at grazing angles and over‐saturated colors on rough surfaces, which causes an unnatural appearance that is not observed in ground truth data. We address this problem by taking the distribution of light directions, given by the environment map and surface roughness, into account when evaluating the reflectance term. In particular, our approach prefilters the first and second moments of the light direction, which are used to evaluate a filtered version of the reflectance term. We show that the visual quality of our approach is superior to the ones previously achieved, while having only a small negative impact on performance.
Wide Gamut Spectral Upsampling with Fluorescence
Authors: Jung A. , Wilkie A. , Hanika J. , Jakob W. , Dachsbacher C. 
Published: July 2019

AbstractPhysically based spectral rendering has become increasingly important in recent years. However, asset textures in such systems are usually still drawn or acquired as RGB tristimulus values. While a number of RGB to spectrum upsampling techniques are available, none of them support upsampling of all colours in the full spectral locus, as it is intrinsically bigger than the gamut of physically valid reflectance spectra. But with display technology moving to increasingly wider gamuts, the ability to achieve highly saturated colours becomes an increasingly important feature.Real materials usually exhibit smooth reflectance spectra, while computationally generated spectra become more blocky as they represent increasingly bright and saturated colours. In print media, plastic or textile design, fluorescent dyes are added to extend the boundaries of the gamut of reflectance spectra.We follow the same approach for rendering: we provide a method which, given an input RGB tristimulus value, automatically provides a mixture of a regular, smooth reflectance spectrum plus a fluorescent part. For highly saturated input colours, the combination yields an improved reconstruction compared to what would be possible relying on a reflectance spectrum alone. At the core of our technique is a simple parametric spectral model for reflectance, excitation, and emission that allows for compact storage and is compatible with texture mapping. The model can then be used as a fluorescent diffuse component in an existing more complex BRDF model. We also provide importance sampling routines for practical application in a path tracer.
Analytic Spectral Integration of Birefringence‐Induced Iridescence
Authors: Steinberg S. 
Published: July 2019

AbstractOptical phenomena that are only observable in optically anisotropic materials are generally ignored in the computer graphics. However, such optical effects are not restricted to exotic materials and can also be observed with common translucent objects when optical anisotropy is induced, e.g. via mechanical stress. Furthermore accurate prediction and reproduction of those optical effects has important practical applications. We provide a short but complete analysis of the relevant electromagnetic theory of light propagation in optically anisotropic media and derive the full set of formulations required to render birefringent materials. We then present a novel method for spectral integration of refraction and reflection in an anisotropic slab. Our approach allows fast and robust rendering of birefringence‐induced iridescence in a physically faithful manner and is applicable to both real‐time and offline rendering.
Adaptive BRDF‐Oriented Multiple Importance Sampling of Many Lights
Authors: Liu Yifan , Xu Kun , Yan Ling‐Qi 
Published: July 2019

AbstractMany‐light rendering is becoming more common and important as rendering goes into the next level of complexity. However, to calculate the illumination under many lights, state of the art algorithms are still far from efficient, due to the separate consideration of light sampling and BRDF sampling. To deal with the inefficiency of many‐light rendering, we present a novel light sampling method named BRDF‐oriented light sampling, which selects lights based on importance values estimated using the BRDF's contributions. Our BRDF‐oriented light sampling method works naturally with MIS, and allows us to dynamically determine the number of samples allocated for different sampling techniques. With our method, we can achieve a significantly faster convergence to the ground truth results, both perceptually and numerically, as compared to previous many‐light rendering algorithms.
Orthogonal Array Sampling for Monte Carlo Rendering
Authors: Jarosz Wojciech , Enayet Afnan , Kensler Andrew , Kilpatrick Charlie , Christensen Per 
Published: July 2019

AbstractWe generalize N‐rooks, jittered, and (correlated) multi‐jittered sampling to higher dimensions by importing and improving upon a class of techniques called orthogonal arrays from the statistics literature. Renderers typically combine or “pad” a collection of lower‐dimensional (e.g. 2D and 1D) stratified patterns to form higher‐dimensional samples for integration. This maintains stratification in the original dimension pairs, but looses it for all other dimension pairs. For truly multi‐dimensional integrands like those in rendering, this increases variance and deteriorates its rate of convergence to that of pure random sampling. Care must therefore be taken to assign the primary dimension pairs to the dimensions with most integrand variation, but this complicates implementations. We tackle this problem by developing a collection of practical, in‐place multi‐dimensional sample generation routines that stratify points on all t‐dimensional and 1‐dimensional projections simultaneously. For instance, when t=2, any 2D projection of our samples is a (correlated) multi‐jittered point set. This property not only reduces variance, but also simplifies implementations since sample dimensions can now be assigned to integrand dimensions arbitrarily while maintaining the same level of stratification. Our techniques reduce variance compared to traditional 2D padding approaches like PBRT's (0,2) and Stratified samplers, and provide quality nearly equal to state‐of‐the‐art QMC samplers like Sobol and Halton while avoiding their structured artifacts as commonly seen when using a single sample set to cover an entire image. While in this work we focus on constructing finite sampling point sets, we also discuss potential avenues for extending our work to progressive sequences (more suitable for incremental rendering) in the future.
Distributing Monte Carlo Errors as a Blue Noise in Screen Space by Permuting Pixel Seeds Between Frames
Authors: Heitz E. , Belcour L. 
Published: July 2019

AbstractRecent work has shown that distributing Monte Carlo errors as a blue noise in screen space improves the perceptual quality of rendered images. However, obtaining such distributions remains an open problem with high sample counts and high‐dimensional rendering integrals. In this paper, we introduce a temporal algorithm that aims at overcoming these limitations. Our algorithm is applicable whenever multiple frames are rendered, typically for animated sequences or interactive applications. Our algorithm locally permutes the pixel sequences (represented by their seeds) to improve the error distribution across frames. Our approach works regardless of the sample count or the dimensionality and significantly improves the images in low‐varying screen‐space regions under coherent motion. Furthermore, it adds negligible overhead compared to the rendering times. Note: our supplemental material provides more results with interactive comparisons against previous work.
Combining Point and Line Samples for Direct Illumination
Authors: Salesin Katherine , Jarosz Wojciech 
Published: July 2019

AbstractWe develop a unified framework for combining point and line samples in direct lighting calculations. While line samples have proven beneficial in a variety of rendering contexts, their application in direct lighting has been limited due to a lack of formulas for evaluating advanced BRDFs along a line and performance tied to the orientation of occluders in the scene. We lift these limitations by elevating line samples to a shared higher‐dimensional space with point samples. Our key insight is to separate the probability distribution functions of line samples and points that lie along a line sample. This simple conceptual change allows us to apply multiple importance sampling (MIS) between points and lines, and lines with each other, in order to leverage their respective strengths. We also show how to improve the convergence rate of MIS between points and lines in an unbiased way using a novel discontinuity‐smoothing balance heuristic. We verify through a set of rendering experiments that our proposed MISing of points and lines, and lines with each other, reduces variance of the direct lighting estimate while supporting an increased range of BSDFs compared to analytic line integration.
Learned Fitting of Spatially Varying BRDFs
Authors: Merzbach S. , Hermann M. , Rump M. , Klein R. 
Published: July 2019

AbstractThe use of spatially varying reflectance models (SVBRDF) is the state of the art in physically based rendering and the ultimate goal is to acquire them from real world samples. Recently several promising deep learning approaches have emerged that create such models from a few uncalibrated photos, after being trained on synthetic SVBRDF datasets. While the achieved results are already very impressive, the reconstruction accuracy that is achieved by these approaches is still far from that of specialized devices. On the other hand, fitting SVBRDF parameter maps to the gibabytes of calibrated HDR images per material acquired by state of the art high quality material scanners takes on the order of several hours for realistic spatial resolutions. In this paper, we present a first deep learning approach that is capable of producing SVBRDF parameter maps more than two orders of magnitude faster than state of the art approaches, while still providing results of equal quality and generalizing to new materials unseen during the training. This is made possible by training our network on a large‐scale database of material scans that we have gathered with a commercially available SVBRDF scanner. In particular, we train a convolutional neural network to map calibrated input images to the 13 parameter maps of an anisotropic Ward BRDF, modified to account for Fresnel reflections, and evaluate the results by comparing the measured images against re‐renderings from our SVBRDF predictions. The novel approach is extensively validated on real world data taken from our material database, which we make publicly available under https://cg.cs.uni‐bonn.de/svbrdfs/.
Risk factors for hemorrhage of brain arteriovenous malformation
Authors: Shaligram Sonali S. , Winkler Ethan , Cooke Daniel , Su Hua 
Published: July 2019

AbstractPatients with brain arteriovenous malformation (bAVM) are at risk of intracranial hemorrhage (ICH). Overall, bAVM accounts for 25% of hemorrhagic strokes in adults <50 years of age. The treatment of unruptured bAVMs has become controversial, because the natural history of these patients may be less morbid than invasive therapies. Available treatments include observation, surgical resection, endovascular embolization, stereotactic radiosurgery, or combination thereof. Knowing the risk factors for bAVM hemorrhage is crucial for selecting appropriate therapeutic strategies. In this review, we discussed several biological risk factors, which may contribute to bAVM hemorrhage.
The Aortic Calcification Index is a risk factor associated with anastomotic leakage after anterior resection of rectal cancer
Authors: Shen Z. , An Y. , Shi Y. , Yin M. , Xie Q. , Gao Z. , Jiang K. , Wang S. , Ye Y. 
Published: July 2019

AbstractAimAnastomotic leakage (AL) is one of the most feared postoperative complications after anterior resection (AR) of rectal cancer. An adequate blood supply at the anastomotic site is regarded as a prerequisite for healing. We hypothesize that the Aortic Calcification Index (ACI) might reflect the severity of atherosclerosis in patients, and thereby be a risk factor for AL.MethodAL was investigated retrospectively according to the definition of the International Study Group of Rectal Cancer in 423 rectal cancer patients who underwent anterior rectal resection. The ACI was measured by preoperative abdominal CT scan. The cross‐section of the aorta was evenly divided into 12 sectors, the number of calcified sectors was counted as the calcification score of each slice. Lasso logistic regression and multivariate regression analysis were used to identify risk factors for AL.ResultsThe percentage of AL after AR was 7.8% (33/423); the mortality of patients who sustained a leak was 3.0% (1/33). Patients with a high ACI had a significantly higher percentage of AL than patients with low ACI (11.2% vs 5.6%, P = 0.04). Among patients with AL, a higher ACI was associated with greater severity of AL (the ACI of patients with grade A leakage, grade B leakage and grade C leakage was 0.5% ± 0.2%, 11.5% ± 9.2% and 24.2% ± 21.7%, respectively; P = 0.008). After risk adjustment, multivariate regression analysis showed that a higher ACI was an independent risk factor for AL (OR 2.391, P = 0.04).ConclusionA high ACI might be an important prognostic factor for AL after AR for rectal cancer. Confirmatory studies are required.
Cutaneous neoplasms composed of melanoma and carcinoma: A rare but important diagnostic pitfall and review of the literature
Authors: Mejbel Haider A. , Nelson Kelly C. , Pradhan Dinesh , Ivan Doina , Zaleski Michael , Nagarajan Priyadharsini , Tetzlaff Michael T. , Curry Jonathan L. , Torres‐Cabala Carlos A. , Prieto Victor G. , Aung Phyu P. 
Published: July 2019

AbstractWe report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5‐mm pink‐blue macule over the right zygomatic arch in an 85‐year‐old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART‐1, with high Ki‐67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan‐cytokeratin and Ber‐EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease‐free at 9 months after the initial diagnosis. The second tumor presented as a 6‐mm pink‐brown crusted papule on the right forehead in an 89‐year‐old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART‐1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM‐SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic‐epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.
Modeling development of frontal electroencephalogram (EEG) asymmetry: Sex differences and links with temperament
Authors: Gartstein Maria A. , Hancock Gregory R. , Potapova Natalia V. , Calkins Susan D. , Bell Martha Ann 
Published: July 2019

AbstractAsymmetric patterns of frontal brain electrical activity reflect approach and avoidance tendencies, with stability of relative right activation associated with withdrawal emotions/motivation and left hemisphere activation linked with approach and positive affect. However, considerable shifts in approach/avoidance‐related lateralization have been reported for children not targeted because of extreme temperament. In this study, dynamic effects of frontal electroencephalogram (EEG) power within and across hemispheres were examined throughout early childhood. Specifically, EEG indicators at 5, 10, 24, 36, 48, and 72 months‐of‐age (n = 410) were analyzed via a hybrid of difference score and panel design models, with baseline measures and subsequent time‐to‐time differences modeled as potentially influencing all subsequent amounts of time‐to‐time change (i.e., predictively saturated). Infant sex was considered as a moderator of dynamic developmental effects, with temperament attributes measured at 5 months examined as predictors of EEG hemisphere development. Overall, change in left and right frontal EEG power predicted declining subsequent change in the same hemisphere, with effects on the opposing neurobehavioral system enhancing later growth. Infant sex moderated the pattern of within and across‐hemisphere effects, wherein for girls more prominent left hemisphere influences on the right hemisphere EEG changes were noted and right hemisphere effects were more salient for boys. Largely similar patterns of temperament prediction were observed for the left and the right EEG power changes, with limited sex differences in links between temperament and growth parameters. Results were interpreted in the context of comparable analyses using parietal power values, which provided evidence for unique frontal effects.