Harmonic Networks: Deep Translation and Rotation Equivariance

Translating or rotating an input image should not affect the results of many computer vision tasks. Convolutional neural networks (CNNs) are already translation equivariant: input image translations produce proportionate feature map translations. This is not the case for rotations. Global rotation equivariance is typically sought through data augmentation, but patch-wise equivariance is more difficult. We present Harmonic Networks or H-Nets, a CNN exhibiting equivariance to patch-wise translation and 360-rotation. We achieve this by replacing regular CNN filters with circular harmonics, returning a maximal response and orientation for every receptive field patch. H-Nets use a rich, parameter-efficient and low computational complexity representation, and we show that deep feature maps within the network encode complicated rotational invariants. We demonstrate that our layers are general enough to be used in conjunction with the latest architectures and techniques, such as deep supervision and batch normalization. We also achieve state-of-the-art classification on rotated-MNIST, and competitive results on other benchmark challenges

EZETIMIBE PROTECTS THP-1 CELLS FROM ISCHEMIA-REPERFUSION INJURY REDUCING OXIDATIVE STRESS AND UP-REGULATING NRF2/ ARE GENE EXPRESSION

Background and Aims: We demonstrated that physical training, characterized by repeated ischemia-reperfusion (I-R) episodes (ischemic conditioning, IC), protects circulating cells from peripheral artery disease (PAD) patients against ischemic harms by reducing oxidative stress (OS) and by up-regulating nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway expression. Ezetimibe (Eze) has been shown to alleviate OS enhancing Nrf2 nuclear translocation in an AMPK/p62-dependent manner. In a cellular I-R and IC model, we aimed to investigate: 1) the effect of Eze on OS and Nrf2/ARE gene expression 2) whether Eze could have a synergistic effect on IC. Methods: THP-1 cells were treated with or without Eze (50mM) overnight, then subjected to 1 or 6 repetitive I-R cycles using EVOS FL Auto Imaging System. Reactive oxygen species (ROS) formation was evaluated with DCF in cytofluorimetry. Nrf2/ARE and p62 gene expression were evaluated by RT-PCR and western blotting. Results: When THP-1 cells were exposed to 1 I-R cycle, the preincubation with Eze significantly reduced ROS formation (p<0.01) and up-regulated Nrf2/ARE pathway expression and p62 phosphorylation (p<0.001). Multiple I-R cycles, acting as IC, significantly reduced ROS formation and upregulated Nrf2/ARE gene expression (p<0.001); in these conditions, Eze preincubation was able not only to almost abolish ROS formation (p<0.01) but also further up-regulate Nrf2/ARE expression. Conclusions: In our I-R model, Eze not only restores I-R-induced oxidative damages through Nrf2/ARE signaling up-regulation but also has a synergistic effect on IC. This new \u201cpleiotropic\u201d effect, if confirmed in vivo, may strengthen the use of Eze in PAD patien

Magnetic Surgical Instruments for Robotic Abdominal Surgery.

This review looks at the implementation of magnetic-based approaches in surgical instruments for abdominal surgeries. As abdominal surgical techniques advance toward minimizing surgical trauma, surgical instruments are enhanced to support such an objective through the exploration of magnetic-based systems. With this design approach, surgical devices are given the capabilities to be fully inserted intraabdominally to achieve access to all abdominal quadrants, without the conventional rigid link connection with the external unit. The variety of intraabdominal surgical devices are anchored, guided, and actuated by external units, with power and torque transmitted across the abdominal wall through magnetic linkage. This addresses many constraints encountered by conventional laparoscopic tools, such as loss of triangulation, fulcrum effect, and loss/lack of dexterity for surgical tasks. Design requirements of clinical considerations to aid the successful development of magnetic surgical instruments, are also discussed

Discriminating ripple-fire explosions with high frequency (>20 Hz) data

With a Comprehensive Test Ban (CTB), discriminating ripple-fired explosions from mining operations becomes important. Different methods have been proposed to discriminate these explosions, most of which use the modulations seen in the spectra of ripple-fired blasts. The Deployable Seismic Verification System (DSVS) in Wyoming records data at frequencies up to 50 Hz, and provides an opportunity to determine if there are any operational benefits to discriminate ripple-fired explosions from using high frequency (> 20 Hz) data. We collected a database of 646 events consisting of 118 known earthquakes, 1 known rockburst, 176 known ripple-fired quarry blasts and 351 unknown signals. Binary spectrograms for each event were calculated using a 2.5 second window, 5/8 overlap and 10% cosine window. We used a frequency band of 0 to 50 Hz. A blind test was done to choose events that appeared to have spectral banding indicative of ripple-fire explosions. One hundred fifty one events were picked as ripple-fire explosions by both authors; 59 of these events are known quarry blasts. To remove the ambiguities introduced using human analysts, we calculated an average binary spectrum for each event following a method similar to Wuster (1993). A criterion was developed so that events with six or more peaks over 0.8 and/or nulls under 0.2 was declared a ripple-fire explosion. With this method, 251 events were chosen as ripple-fire explosions, 91 of them known quarry blasts

Influence of post and resin cement on stress distribution of maxillary central incisors restored with direct resin composite

The current study evaluated the influence of two endodontic post systems and the elastic modulus and film thickness of resin cement on stress distribution in a maxillary central incisor (MCI) restored with direct resin composite using finite element analysis (FEA). A three-dimensional model of an MCI with a coronary fracture and supporting structures was performed. A static chewing pressure of 2.16 N/mm2 was applied to two areas on the palatal surface of the composite restoration. Zirconia ceramic (ZC) and glass fiber (GF) posts were considered. The stress distribution was analyzed in the post, dentin and cement layer when ZC and GF posts were fixed to the root canals using resin cements of different elastic moduli (7.0 and 18.6 GPa) and different layer thicknesses (70 and 200 μm). The different post materials presented a significant influence on stress distribution with lesser stress concentration when using the GF post. The higher elastic modulus cement created higher stress levels within itself. The cement thicknesses did not present significant changes.34222322

Interpretable transformations with Encoder-Decoder Networks

Deep feature spaces have the capacity to encode complex transformations of their input data. However, understanding the relative feature-space relationship between two transformed encoded images is difficult. For instance, what is the relative feature space relationship between two rotated images? What is decoded when we interpolate in feature space? Ideally, we want to disentangle confounding factors, such as pose, appearance, and illumination, from object identity. Disentangling these is difficult because they interact in very nonlinear ways. We propose a simple method to construct a deep feature space, with explicitly disentangled representations of several known transformations. A person or algorithm can then manipulate the disentangled representation, for example, to re-render an image with explicit control over parameterized degrees of freedom. The feature space is constructed using a transforming encoder-decoder network with a custom feature transform layer, acting on the hidden representations. We demonstrate the advantages of explicit disentangling on a variety of datasets and transformations, and as an aid for traditional tasks, such as classification

On the appearance of Eisenstein series through degeneration

Let $\Gamma$ be a Fuchsian group of the first kind acting on the hyperbolic upper half plane $\mathbb H$, and let $M = \Gamma \backslash \mathbb H$ be the associated finite volume hyperbolic Riemann surface. If $\gamma$ is parabolic, there is an associated (parabolic) Eisenstein series, which, by now, is a classical part of mathematical literature. If $\gamma$ is hyperbolic, then, following ideas due to Kudla-Millson, there is a corresponding hyperbolic Eisenstein series. In this article, we study the limiting behavior of parabolic and hyperbolic Eisenstein series on a degenerating family of finite volume hyperbolic Riemann surfaces. In particular, we prove the following result. If $\gamma \in \Gamma$ corresponds to a degenerating hyperbolic element, then a multiple of the associated hyperbolic Eisenstein series converges to parabolic Eisenstein series on the limit surface.Comment: 15 pages, 2 figures. This paper has been accepted for publication in Commentarii Mathematici Helvetic

RTN in GexSe1-x OTS Selector Devices

Random telegraph noise (RTN) signals in GexSe1-x ovonic threshold switching (OTS) selector have been analyzed in this work, both before and after the first-fire (FF) operation and at on- and off-states. It is observed that RTN appears after the FF, and its absolute amplitude at the off-state is small and negligible in comparison with the RTN signals in RRAM devices. At the on-state, large RTN signals are observed, which can either partially or fully block the conduction path, supporting that a conductive filament is formed or activated by FF and then modulated during switching. Statistical analysis reveals that the relative RTN amplitude at on-state in GexSe1-x OTS selector is smaller than or equivalent to those in RRAM devices

Evaluation of a novel low-cost disposable endoscope for visual assessment of the esophagus and stomach in an ex-vivo phantom model

Background and study aims Our academic lab has developed a novel, low-cost, disposable endoscope for assessment of the esophagus and stomach without need for large equipment or complex electronics. Usability and intuitiveness of the platform are unknown. Methods The novel endoscope (NE) consists of a high-definition camera, LED module, and three bellows. Compressed air actuates the bellows, producing camera/LED articulation. Insufflation and lens cleaning ports are present. Video can be displayed on any monitor. Total material costs less than $ 35 US. Five novices, five fellows, and five attendings performed five trials using a conventional endoscope and the NE on an upper tract phantom with six gastric landmarks marked. Outcomes included successful identification and time to landmarks; and intuitiveness (NASA task load index; user comments). Results All landmarks were successfully identified with both endoscopes for all trials (n = 900). Attendings and fellows were quicker with the conventional endoscope when compared to the NE (24.48 v 37.13s; P < 0.01). There was no significant time difference between platforms for novices (P = 0.16). All users found the NE intuitive with low mental and physical demand. Novices reported lower temporal demand and effort when using the NE. Conclusions The NE was easy to maneuver, intuitive, and successful at visualizing gastric landmarks. All users were pleased with the NE drive mechanism and were successful at visualizing the gastric landmarks in a clinically acceptable time. The novel platform has the potential to facilitate rapid, low-cost, diagnostic assessment of the esophagus and stomach in non-traditional settings – facilitating patient management decisions, minimizing encumbrance, and avoiding cross-contamination