1,212 research outputs found
Animal Models for Periodontal Disease
Animal models and cell cultures have contributed new knowledge in biological sciences, including periodontology. Although cultured cells can be used to study physiological processes that occur during the pathogenesis of periodontitis, the complex host response fundamentally responsible for this disease cannot be reproduced in vitro. Among the animal kingdom, rodents, rabbits, pigs, dogs, and nonhuman primates have been used to model human periodontitis, each with advantages and disadvantages. Periodontitis commonly has been induced by placing a bacterial plaque retentive ligature in the gingival sulcus around the molar teeth. In addition, alveolar bone loss has been induced by inoculation or injection of human oral bacteria (e.g., Porphyromonas gingivalis) in different animal models. While animal models have provided a wide range of important data, it is sometimes difficult to determine whether the findings are applicable to humans. In addition, variability in host responses to bacterial infection among individuals contributes significantly to the expression of periodontal diseases. A practical and highly reproducible model that truly mimics the natural pathogenesis of human periodontal disease has yet to be developed
Improving temperature estimation in low-cost infrared cameras using deep neural networks
Low-cost thermal cameras are inaccurate (usually ) and have
space-variant nonuniformity across their detector. Both inaccuracy and
nonuniformity are dependent on the ambient temperature of the camera. The main
goal of this work was to improve the temperature accuracy of low-cost cameras
and rectify the nonuniformity.
A nonuniformity simulator that accounts for the ambient temperature was
developed. An end-to-end neural network that incorporates the ambient
temperature at image acquisition was introduced. The neural network was trained
with the simulated nonuniformity data to estimate the object's temperature and
correct the nonuniformity, using only a single image and the ambient
temperature measured by the camera itself. Results show that the proposed
method lowered the mean temperature error by approximately compared
to previous works. In addition, applying a physical constraint on the network
lowered the error by an additional .
The mean temperature error over an extensive validation dataset was
. The method was verified on real data in the field and produced
equivalent results
Chiral gravity in two dimensions
It is shown that conformal matter with c_{\ssc L}\not=c_{\ssc R} can be
consistently coupled to two-dimensional `frame' gravity. The theory is
quantized, following David, and Distler and Kawai, using the derivation of
their {\it ansatz} due to Mavromatos and Miramontes, and D'Hoker and Kurzepa.
New super-selection rules are found by requiring SL(2,{\bf C}) invariance of
correlation functions on the plane. There is no analogue of the barrier
found in non-chiral non-critical strings. A non-critical heterotic string is
constructed---it has 744 states in its spectrum, transforming in the adjoint
representation of Correlation functions are calculated in this
example.Comment: 19 pages, iassns-hep-92-19/McGill/92-2
Simultaneous temperature estimation and nonuniformity correction from multiple frames
Infrared (IR) cameras are widely used for temperature measurements in various
applications, including agriculture, medicine, and security. Low-cost IR camera
have an immense potential to replace expansive radiometric cameras in these
applications, however low-cost microbolometer-based IR cameras are prone to
spatially-variant nonuniformity and to drift in temperature measurements, which
limits their usability in practical scenarios.
To address these limitations, we propose a novel approach for simultaneous
temperature estimation and nonuniformity correction from multiple frames
captured by low-cost microbolometer-based IR cameras. We leverage the physical
image acquisition model of the camera and incorporate it into a deep learning
architecture called kernel estimation networks (KPN), which enables us to
combine multiple frames despite imperfect registration between them. We also
propose a novel offset block that incorporates the ambient temperature into the
model and enables us to estimate the offset of the camera, which is a key
factor in temperature estimation.
Our findings demonstrate that the number of frames has a significant impact
on the accuracy of temperature estimation and nonuniformity correction.
Moreover, our approach achieves a significant improvement in performance
compared to vanilla KPN, thanks to the offset block. The method was tested on
real data collected by a low-cost IR camera mounted on a UAV, showing only a
small average error of relative to costly
scientific-grade radiometric cameras.
Our method provides an accurate and efficient solution for simultaneous
temperature estimation and nonuniformity correction, which has important
implications for a wide range of practical applications
Supersymmetric Cycles in Exceptional Holonomy Manifolds and Calabi-Yau 4-Folds
We derive in the SCFT and low energy effective action frameworks the necessary and sufficient conditions for supersymmetric cycles in exceptional holonomy manifolds and Calabi-Yau 4-folds. We show that the Cayley cycles in holonomy eight-manifolds and the associative and coassociative cycles in holonomy seven-manifolds preserve half of the space-time supersymmetry. We find that while the holomorphic and special Lagrangian cycles in Calabi-Yau 4-folds preserve half of the space-time supersymmetry, the Cayley submanifolds are novel as they preserve only one quarter of it. We present some simple examples. Finally, we discuss the implications of these supersymmetric cycles on mirror symmetry in higher dimensions
A novel familial mutation in the PCSK1 gene that alters the oxyanion hole residue of proprotein convertase 1/3 and impairs its enzymatic activity.
Four siblings presented with congenital diarrhea and various endocrinopathies. Exome sequencing and homozygosity mapping identified five regions, comprising 337 protein-coding genes that were shared by three affected siblings. Exome sequencing identified a novel homozygous N309K mutation in the proprotein convertase subtilisin/kexin type 1 (PCSK1) gene, encoding the neuroendocrine convertase 1 precursor (PC1/3) which was recently reported as a cause of Congenital Diarrhea Disorder (CDD). The PCSK1 mutation affected the oxyanion hole transition state-stabilizing amino acid within the active site, which is critical for appropriate proprotein maturation and enzyme activity. Unexpectedly, the N309K mutant protein exhibited normal, though slowed, prodomain removal and was secreted from both HEK293 and Neuro2A cells. However, the secreted enzyme showed no catalytic activity, and was not processed into the 66 kDa form. We conclude that the N309K enzyme is able to cleave its own propeptide but is catalytically inert against in trans substrates, and that this variant accounts for the enteric and systemic endocrinopathies seen in this large consanguineous kindred
Supersymmetric cycles in exceptional holonomy manifolds and Calabi-Yau four-folds
We derive in the SCFT and low energy effective action frameworks the necessary and sufficient conditions for supersymmetric cycles in exceptional holonomy manifolds and Calabi-Yau four-folds. We show that the Cayley cycles in Spin(7) holonomy eight-manifolds and the associative and coassociative cycles in G2 holonomy seven-manifolds preserve half of the space-time supersymmetry. We find that while the holomorphic and special Lagrangian cycles in Calabi-Yau four-folds preserve half of the space-time supersymmetry, the Cayley submanifolds are novel as they preserve only one quarter of it. We present some simple examples. Finally, we discuss the implications of these supersymmetric cycles on mirror symmetry in higher dimensions
Kac-Moody structure of chiral gravity in the light-cone gauge
We study the residual symmetry of the chiral gravity in
the light-cone gauge. Quantum gravitational effects renormalize the Kac-Moody
central charge and introduce, through the Lorentz anomaly, an arbitrary
parameter. Due to the presence of this free parameter the Kac-Moody central
charge has no forbidden range of values, and the strong gravity regime is open
to investigations.Comment: 13 Pages, Phyzz
Modeling payback from research into the efficacy of left-ventricular assist devices as destination therapy
Objectives: Ongoing developments in design have improved the outlook for left-ventricular assist device (LVAD) implantation as a therapy in end-stage heart failure. Nevertheless, early cost-effectiveness assessments, based on first-generation devices, have not been encouraging. Against this background, we set out (i) to examine the survival benefit that LVADs would need to generate before they could be deemed cost-effective; (ii) to provide insight into the likelihood that this benefit will be achieved; and (iii) from the perspective of a healthcare provider, to assess the value of discovering the actual size of this benefit by means of a Bayesian value of information analysis.
Methods: Cost-effectiveness assessments are made from the perspective of the healthcare provider, using current UK norms for the value of a quality-adjusted life-year (QALY). The treatment model is grounded in published analyses of the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial of first-generation LVADs, translated into a UK cost setting. The prospects for patient survival with second-generation devices is assessed using Bayesian prior distributions, elicited from a group of leading clinicians in the field.
Results: Using established thresholds, cost-effectiveness probabilities under these priors are found to be low (.2 percent) for devices costing as much as £60,000. Sensitivity of the conclusions to both device cost and QALY valuation is examined.
Conclusions: In the event that the price of the device in use would reduce to £40,000, the value of the survival information can readily justify investment in further trials
Gravitational F-terms of N=1 Supersymmetric SU(N) Gauge Theories
We use the generalized Konishi anomaly equations and R-symmetry anomaly to
compute the exact perturbative and non-perturbative gravitational F-terms of
four-dimensional N=1 supersymmetric gauge theories. We formulate the general
procedure for computation and consider chiral and non-chiral SU(N) gauge
theories.Comment: 25 pages, v2: minor changes in section 4, references adde
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