285 research outputs found
sj-pdf-1-aja-10.1177_15333175221085066 – Supplemental Material for Regulation of the Late Onset alzheimer’s Disease Associated <i>HLA-DQA1/DRB1</i> Expression
No full textSupplemental Material, sj-pdf-1-aja-10.1177_15333175221085066 for Regulation of the Late Onset alzheimer’s Disease Associated HLA-DQA1/DRB1 Expression by Xiaoyu Zhang, Meijaun Zou, Yuwei Wu, Danli Jiang, Ting Wu, Yihan Zhao, Di Wu, Jing Cui and Gang Li in American Journal of Alzheimer's Disease & Other Dementias</p
An efficient approach to probe bioactive components of herbal patches by 2D-carbon microfiber fractionation and multi-chamber membrane separation electrophoresis: Spatholobus suberectus Dunn as a case
No full textHerbal patches are widely used in clinics for their good curative effects. However, due to the complexity of plant matrices and the extremely low content of transdermal components, the individuation of their effective bioactive compounds represents a challenge: there is then a great need for an efficient method to reveal the bioactive ingredients of herbal patches. In this work, a wide-screening approach is proposed to an individuation of transdermal bioactive components in herbal patches obtained by Spatholobus suberectus Dunn (S. suberectus). Using a two-dimensional microscale carbon fiber/active carbon fiber system combined with a quadrupole time-of-flight high-resolution mass spectrometry (2DμCFs-QTOF-HRMS), a rapid and comprehensive analysis, lasting only 5 min, allowed the identification of 45 distinct polar components within S. suberectus extracts. Among these, 30 components exhibited a transdermal penetration estimated at values higher than 10 %. The key target, predicted by bioinformatics, was prostaglandin-endoperoxide synthase 2 (PTGS2). From the transdermal components of S. suberectus, four potential inhibitors of PTGS2 (protocatechuic acid, isoliquiritigenin, medicarpin, and catechin) were screened by multi-chamber membrane separation electrophoresis (MCMSE). The presence of binding pockets and action sites for medicarpin, isoliquiritigenin, and catechin determines higher binding energy towards PTGS2, with lower IC50 values (12.27, 9.08, and 41.68 μM, respectively). The high-throughput and high-sensitivity analysis by 2DμCFs-QTOF-HRMS, combined with a high-accuracy screening of MCMSE, provides strong technical support for the discovery of trace transdermal bioactive components of herbal patches. The integration of the two technologies could accelerate the study of action mechanisms, quality control, and product improvement of herbal patches
Micro-scale Fracture Toughness Testing and Finite Element Analysis of Transparent Ceramics
No full textRelative surface energies of low-index planes and the effect of Europium segregants on grain boundary structure and fracture strength of magnesium aluminate spinel (MgAl2O4) bicrystals were evaluated by micro scale fracture tests and high-resolution electron microscopy. Single crystal specimens with {111}, {110}, and {100} boundary planes were bonded together using hot pressing to make {111}/{100} and {100}/{110} interfaces. Certain of the resulting specimens were doped with Eu. Micro cantilever deflection tests were employed to measure fracture toughness within each single crystal and at both bicrystal boundaries. Correlating surface energy with fracture energy measurements, the surface energies of {111}, {110}, and {100} planes were found to have a decreasing trend. High-angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM) was utilized to characterize grain boundary structure and chemistry. Differences in Eu segregation behavior on the two grain boundaries resulted in differences in grain boundary structure and differences in corresponding interfacial fracture strength. Eu segregated more uniformly to the {111}/{100} interface where it bonded strongly to the {111} plane but not to the {100} plane. The doped {100}/{110} boundary was characterized by a lack of uniform segregation. Corresponding fractography work and an in-situ foil fracture test was carried out in addition at the interface, aiding the structure and fracture behavior analysis. Here, we demonstrate how micro-cantilever fracture toughness measurements on single crystal and individual grain boundaries can indicate surface energy trends. And by combining micro fracture tests and HAADF-STEM analysis, a method to investigate the correlation between the grain boundary structure and fracture strength was established to interpret how rare earth segregation behavior affects intrinsic toughening mechanisms of magnesium aluminate spinel.In recognition of the shortcomings of the microcantilever bend fracture test, a new micro-scale fracture test that uses a bowtie-shaped micro-beam specimen with a chevron notch was designed and employed in transparent ceramic toughness testing. This clamped-clamped specimen can produce stable crack growth in brittle materials. Cyclic loading causes progressive crack extension, thereby producing multiple fracture toughness results in one experiment. The symmetric geometry eliminates the mixed mode fracture that exists in single-ended cantilevers. A 3D finite element analysis (FEA) model built in ANSYS Mechanical APDL and Altair Hypermesh was used to relate the crack length to the beam compliance. Full analysis of the bowtie chevron specimen geometry sensitivity has been carried out with FEA. A detailed crack stability analysis was conducted combining different nano-mechanical testing system, loading conditions, FEA analysis and TEM experimental methods. MATLAB programming was utilized to process large experimental data and to apply a polynomial fit in establishing a compliance and crack extension length relationship. The fracture energy could then be evaluated using an energy approach (‘Work of Fracture’) by combining FEA and experimental data. The results of tests using fused quartz and a glass-ceramic material match very well with published fracture toughness values. This validates the new micro scale testing method that possesses a combination of advantages not available in any other testing methods
A Comprehensive Understanding of Machine Learning and Deep Learning Methods for 3D Architectural Cultural Heritage Point Cloud Semantic Segmentation
No full textAs a result of the development of Artificial Intelligence (AI) techniques, in recent years, machine learning (ML) and deep learning (DL) approaches have been widely used to semantically enrich 3D architectural cultural heritage (ACH) point clouds. While existing approaches for analyzing and interpreting point clouds continue to improve, the generalizability of pre-trained ML and DL methods to various types of historic buildings remains uncertain. In this context, a comprehensive understanding of both methodologies can enable us to make more effective use of AI techniques in the ACH domain (e.g., data exploitation, model definition, analysis, and preservation). This work presents and compares two very different approaches for the 3D ACH semantic segmentation task. Specifically, we train and test a ML method based on the Random Forest (RF) classifier on the point cloud of three chapels part of the “Sacromonte Calvario di Domodossola” and on the two test scenes of the ArCH dataset. Then, we employ dynamic graph convolutional neural network (DGCNN) as our DL method, training on the ArCH dataset and testing on both the two unseen test scenes of the ArCH dataset and on the “Sacrimonti” chapel point clouds. We provide empirical experiments to illustrate the efficiency of applying ML and DL methodologies to ACH point clouds. Following that, the advantages and limitations of these two approaches are evaluated through a systematic study of the classification results. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
"They're the Same as Any Woman:" Professionals' Awareness of the Unique Needs of Mail Order Brides Who Experience Domestic Violence
No full textFaculty adviser: Dr. Steven M. Harris, Family Social ScienceMail order Brides (MOBs) are women who marry men through international marriage brokers. Usually, MOBs come from less developed countries than their husbands. In recent years, domestic violence in mail order marriages has been brought to public awareness. Although legal protection from government is in place, it is not always sufficient. Community resources, on the other hand, can be helpful for MOBs to escape from domestic violence. Therefore, in order to find out what community resources are available to MOBs who experience domestic violence, the author has conducted 10 interviews with professionals who work in different domestic violence service organizations in the Twin Cities area. This research suggests that only a small number of MOBs have utilized existing community resources. Cultural and language competency as well as an awareness of the unique needs of MOBs who experience domestic violence vary among organizations. Most professionals categorized MOBs as “Immigrants” and saw no difference between the needs of MOBs and those of either all women in general, or immigrant women in particular. Funding cuts and access to MOBs are the main barriers for most organizations in providing appropriate services. One interesting finding from the interviews is related to the term “Mail Order Brides;” as some who were interviewed saw MOBs as victims or other unwitting participants in the sex trafficking industry. This paper adds to our understanding of the unique needs of MOBs who experience domestic violence and whether or not community professionals are adequately prepared to assist them.This research was supported by the Undergraduate Research Opportunities Program (UROP).Wu, Yuwei. (2012). "They're the Same as Any Woman:" Professionals' Awareness of the Unique Needs of Mail Order Brides Who Experience Domestic Violence. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/123436
Scheduling of biological samples for DNA sequencing
No full textThesis (S.M.)--Massachusetts Institute of Technology, Computation for Design and Optimization Program, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 95-97).In a DNA sequencing workflow, a biological sample has to pass through multiple process steps. Two consecutive steps are hydroshearing and library construction. Samples arrive randomly into the inventory and are to complete both processes before their due dates. The research project is to decide the optimal sequence of samples to go through these two processes subject to operational constraints. Two approaches, namely, heuristic and integer programming have been pursued in this thesis. A heuristic algorithm is proposed to solve the scheduling problem. A variant of the problem involving deterministic arrivals of samples is also considered for comparison purposes. Comparison tests between the two approaches are carried out to investigate the performance of the proposed heuristic for the original problem and its variant. Sensitivity analysis of the schedule to parameters of the problem is also conducted when using both approaches.by Yuwei Hu and Chin Soon Lim.S.M
Use of Genomic Data to Resolve Evolutionary Questions in Kangaroo Rats (genus Dipodomys)
No full textHIERARCHICAL NEURAL COMPUTATION IN THE MAMMALIAN VISUAL SYSTEM
No full textOur visual system can efficiently extract behaviorally relevant information from ambiguous and noisy luminance patterns. Although we know much about the anatomy and physiology of the visual system, it remains obscure how the computation performed by individual visual neurons is constructed from the neural circuits. In this thesis, I designed novel statistical modeling approaches to study hierarchical neural computation, using electrophysiological recordings from several stages of the mammalian visual system.
In Chapter 2, I describe a two-stage nonlinear model that characterized both synaptic current and spike response of retinal ganglion cells with unprecedented accuracy. I found that excitatory synaptic currents to ganglion cells are well described by excitatory inputs multiplied by divisive suppression, and that spike responses can be explained with the addition of a second stage of spiking nonlinearity and refractoriness. The structure of the model was inspired by known elements of the retinal circuit, and implies that presynaptic inhibition from amacrine cells is an important mechanism underlying ganglion cell computation.
In Chapter 3, I describe a hierarchical stimulus-processing model of MT neurons in the context of a naturalistic optic flow stimulus. The model incorporates relevant nonlinear properties of upstream V1 processing and explained MT neuron responses to complex motion stimuli. MT neuron responses are shown to be best predicted from distinct excitatory and suppressive components. The direction-selective suppression can impart selectivity of MT neurons to complex velocity fields, and contribute to improved estimation of the three-dimensional velocity of moving objects.
In Chapter 4, I present an extended model of MT neurons that includes both the stimulus-processing component and network activity reflected in local field potentials (LFPs). A significant fraction of the trial-to-trial variability of MT neuron responses is predictable from the LFPs in both passive fixation and a motion discrimination task. Moreover, the choice-related variability of MT neuron responses can be explained by their phase preferences in low-frequency band LFPs. These results suggest an important role of network activity in cortical function.
Together, these results demonstrated that it is possible to infer the nature of neural computation from physiological recordings using statistical modeling approaches
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