390 research outputs found
Route Exploration and Synthesis of The Reported Pyridone-Based PDI Inhibitor STK076545
The enzyme protein disulfide isomerase (PDI) is essential for the correct folding of proteins and the activation of certain cell surface receptors, and is a promising target for the treatment of cancer and thrombotic conditions. A previous high-throughput screen identified the commercial compound STK076545 as a promising PDI inhibitor. To confirm its activity and support further biological studies, a resynthesis was pursued of the reported ÎČ-keto-amide with an N-alkylated pyridone at the α-position. Numerous conventional approaches were complicated by undesired fragmentations or rearrangements. However, a successful 5-step synthetic route was achieved using an aldol reaction with an α-pyridone allyl ester as a key step. An X-ray crystal structure of the final compound confirmed that the reported structure of STK076545 was achieved, however its lack of PDI activity and inconsistent spectral data suggest that the commercial structure was misassigned
GPU-Based Optimization of a Free-Viewpoint Video System
We present a method for optimizing the reconstruction and rendering of 3D objects from multiple images by utilizing the latest features of consumer-level graphics hardware based on shader model 4.0. We accelerate visual hull reconstruction by rewriting a shape-from-silhouette algorithm to execute on the GPU's parallel architecture. Rendering a is optimized through the application of geometry shaders to generate billboarding microfacets textured with captured images. We also present a method for handling occlusion in the camera selection process that is optimized for execution on the GPU. Execution time is further improved by rendering intermediate results directly to texture to minimize the number of data transfers between graphics and main memory. We show our GPU based system to be significantly more efficient than a purely CPU-based approach, due to the parallel nature of the GPU, while maintaining graphical quality
Spatio-temporal prediction of soil moisture using soil maps, topographic indices and SMAP retrievals
Milder winters and extended wetter periods in spring and autumn limit the amount of time available for carrying out ground-based forest operations on soils with satisfactory bearing capacity. Thus, damage to soil in form of compaction and displacement is reported to be becoming more widespread. The prediction of trafficability has become one of the most central issues in planning of mechanized harvesting operations. The work presented looks at methods to model field measured spatio-temporal variations of soil moisture content (SMC, [%vol]) â a crucial factor for soil strength and thus trafficability. We incorporated large-scaled maps of soil characteristics, high-resolution topographic information â depth-to-water (DTW) and topographic wetness index â and openly available temporal soil moisture retrievals provided by the NASA Soil Moisture Active Passive mission. Time-series measurements of SMC were captured at six study sites across Europe. These data were then used to develop linear models, a generalized additive model, and the machine learning algorithms Random Forest (RF) and eXtreme Gradient Boosting (XGB). The models were trained on a randomly selected 10% subset of the dataset. Predictions of SMC made with RF and XGB attained the highest R2 values of 0.49 and 0.51, respectively, calculated on the remaining 90% test set. This corresponds to a major increase in predictive performance, compared to basic DTW maps (R2 = 0.022). Accordingly, the quality for predicting wet soils was increased by 49% when XGB was applied (Matthews correlation coefficient = 0.45). We demonstrated how open access data can be used to clearly improve the prediction of SMC and enable adequate trafficability mappings with high spatial and temporal resolution. Spatio-temporal modelling could contribute to sustainable forest management.publishedVersio
Using Virtual Reality to Enhance Food Technology Education
The use of Virtual Reality (VR) technology combined with 360-degree images and videos provide an opportunity for teachers to bring students into the classroom even when they are located somewhere else. During the COVID-19 lockdown and pandemic, with students across the world forced into home-based learning via remote teaching, a VR classroom shows potential as a tool for adding depth to their learning. The possibility of immersing students in a virtual environment could provide an answer to motivation and engagement issues for todayâs students as well as a solution to some of the current constraints faced by teachers. In particular, VR has the potential to increase the time students are able to spend in (virtual) environments that are suitable for teaching and learning practical skills. With the cost of VR equipment reducing rapidly and the increasing quality of virtual experiences, it appears VR is on the tipping-point of becoming a regular part of school programmes.This article outlines the development and testing of a VR Classroom for the delivery of a food-based lesson with middle school students in a New Zealand school. Kitchens are a costly commodity for schools and the obvious health and safety issues make teaching practical cooking skills challenging. With a focus on student engagement and motivation, data is collected from observation of students using the virtual classroom and a post-test survey. Results show that students were highly motivated and perceived the VR classroom as fun to use
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Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45712/1/11336_2005_Article_BF02289577.pd
Prop-oriented world rotation: enabling passive haptic feedback by aligning real and virtual objects in virtual reality
Passive haptics have long been used to enhance the userâs experience in virtual reality (VR). However, creating props to be used in a virtual environment can be a complicated and lengthy process. Current research looks to create passive haptic props based on the layout of, or objects in, the userâs real environment. However, we identify three key limitations of current research. Firstly, procedural generation introduces many unknown variables into the design process, which complicates applying such techniques to scenarios requiring knowledge of the virtual environmentâs layout ahead of time. Furthermore, such techniques limit the size and dimensions of the virtual space to that of the real space. Lastly, current research necessitates pre-scanning or real-time scanning of the userâs real environment, often requiring specialist equipment and expertise, thus limiting its generalisability. This research proposes PropOrientedWorldRotation, a technique that attempts to answer the aforementioned limitations and simplify the process of adding haptic feedback to VR applications. We implemented this technique in a demonstration game and give an overview of the steps taken to apply the technique in a real context. We analysed the demonstration systemâs performance and conducted an initial user evaluation in three different physical environments. While our stress test of the systemâs performance highlights the necessity for certain optimisations in complex environments, our initial user feedback suggests that users experienced a stronger sense of presence and feelings of safety in our passive haptics-enhanced environment. Hence, we conclude that our proposal has the potential to enhance experiences in VR with haptic feedback
Augmented Perception Through Spatial Scale Manipulation in Virtual Reality for Enhanced Empathy in Design-Related Tasks
This research explores augmented perception by investigating the effects of spatial scale manipulation in Virtual Reality (VR) to simulate multiple levels of virtual eye height (EH) and virtual interpupillary distance (IPD) of the VR users in the design context. We have developed a multiscale VR system for design applications, which supports a dynamic scaling of the VR userâs EH and IPD to simulate different perspectives of multiple userâs groups such as children or persons with disabilities. We strongly believe that VR can improve the empathy of VR users toward the individual sharing or simulating the experience. We conducted a user study comprising two within-subjects designed experiments for design-related tasks with seventeen participants who took on a designerâs role. In the first experiment, the participants performed hazards identification and risks assessment tasks in a virtual environment (VE) while experiencing four different end-user perspectives: a two-year-old child, an eight-year-old child, an adult, and an adult in a wheelchair. We hypothesized that experiencing different perspectives would lead to different design outcomes and found significant differences in the perceived level of risks, the number of identified hazards, and the average height of hazards found. The second experiment had the participants scale six virtual chairs to a suitable scale for different target end-user groups. The participants experienced three perspectives: a two-year-old child, an eight-year-old child, and an adult. We found that when the designerâs perspective matched that of the intended end-user of the product, it yielded significantly lower variance among the designs across participants and more precise scales suitable for the end-user. We also found that the EH and IPD positively correlate with the resulting scales. The key contribution of this work is the evidence to support that spatial scale manipulation of EH and IPD could be a critical tool in the design process to improve the designerâs empathy by allowing them to experience the end-user perspectives. This could influence their design, making a safer or functionally suitable design for various end-user groups with different needs
Histopathology of aortic complications in bicuspid aortic valve versus Marfan syndrome: relevance for therapy?
Patients with bicuspid aortic valve (BAV) and patients with Marfan syndrome (MFS) are more prone to develop aortic dilation and dissection compared to persons with a tricuspid aortic valve (TAV). To elucidate potential common and distinct pathways of clinical relevance, we compared the histopathological substrates of aortopathy. Ascending aortic wall biopsies were divided in five groups: BAV (n = 36) and TAV (n = 23) without and with dilation and non-dilated MFS (n = 8). General histologic features, apoptosis, the expr
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