694 research outputs found
Matrix Li-Yau-Hamilton estimates under Ricci Flow and parabolic frequency
In this paper we prove matrix Li-Yau-Hamilton estimates for positive
solutions to the heat equation and the backward conjugate heat equation, both
coupled with the Ricci flow. We then apply such estimates to establish the
monotonicity of parabolic frequencies up to correction factors. As
applications, we obtain some unique continuation results under the
nonnegativity of sectional or complex sectional curvature.Comment: 37 pages. All comments are welcom
CRISPR/Cas9-mediated gene manipulation to create single-amino-acid-substituted and floxed mice with a cloning-free method.
Clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology is a powerful tool to manipulate the genome with extraordinary simplicity and speed. To generate genetically modified animals, CRISPR/Cas9-mediated genome editing is typically accomplished by microinjection of a mixture of Cas9 DNA/mRNA and single-guide RNA (sgRNA) into zygotes. However, sgRNAs used for this approach require manipulation via molecular cloning as well as in vitro transcription. Beyond these complexities, most mutants obtained with this traditional approach are genetically mosaic, yielding several types of cells with different genetic mutations. Recently, a growing body of studies has utilized commercially available Cas9 protein together with sgRNA and a targeting construct to introduce desired mutations. Here, we report a cloning-free method to target the mouse genome by pronuclear injection of a commercial Cas9 protein:crRNA:tracrRNA:single-strand oligodeoxynucleotide (ssODN) complex into mouse zygotes. As illustration of this method, we report the successful generation of global gene-knockout, single-amino-acid-substituted, as well as floxed mice that can be used for conditional gene-targeting. These models were produced with high efficiency to generate non-mosaic mutant mice with a high germline transmission rate
Holographic Resonant Laser Printing of metasurfaces using plasmonic template
Laser printing with a spatial light modulator (SLM) has several advantages
over conventional raster-writing and dot-matrix display (DMD) writing: multiple
pixel exposure, high power endurance and existing software for computer
generated holograms (CGH). We present a technique for the design and
manufacturing of plasmonic metasurfaces based on ultrafast laser printing with
an SLM. As a proof of principle, we have used this technique to laser print a
plasmonic metalens as well as high resolution plasmonic color decorations. The
high throughput holographic resonant laser printing (HRLP) approach enables
on-demand mass-production of customized metasurfaces.Comment: Supplementary information is available upon request to author
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Experimental evaluation of shear connectors using reactive powder concrete under natural curing condition
Adversarial erasing attention for person re-identification in camera networks under complex environments
Person re-identification (Re-ID) in camera networks under complex environments has achieved promising performance using deep feature representations. However, most approaches usually ignore to learn features from non-salient parts of pedestrian, which results in an incomplete pedestrian representation. In this paper, we propose a novel person Re-ID method named Adversarial Erasing Attention (AEA) to mine discriminative completed features using an adversarial way. Specifically, the proposed AEA consists of the basic network and the complementary network. On the one hand, original pedestrian images are used to train the basic network in order to extract global and local deep features. On the other hand, to learn features complementary to the basic network, we propose the adversarial erasing operation, that locates non-salient areas with the help of attention map, to generate erased pedestrian images. Then, we utilize them to train the complementary network and adopt the dynamic strategy to match the dynamic status of AEA in the learning process. Hence, the diversity of training samples is enriched and the complementary network could discover new clues when learning deep features. Finally, we combine the features learned from the basic and complementary networks to represent the pedestrian image. Experiments on three databases (Market1501, CUHK03 and DukeMTMC-reID) demonstrate the proposed AEA achieves great performances
Data-Driven Modeling of an Unsaturated Bentonite Buffer Model Test Under High Temperatures Using an Enhanced Axisymmetric Reproducing Kernel Particle Method
In deep geological repositories for high level nuclear waste with close
canister spacings, bentonite buffers can experience temperatures higher than
100 {\deg}C. In this range of extreme temperatures, phenomenological
constitutive laws face limitations in capturing the thermo-hydro-mechanical
(THM) behavior of the bentonite, since the pre-defined functional constitutive
laws often lack generality and flexibility to capture a wide range of complex
coupling phenomena as well as the effects of stress state and path dependency.
In this work, a deep neural network (DNN)-based soil-water retention curve
(SWRC) of bentonite is introduced and integrated into a Reproducing Kernel
Particle Method (RKPM) for conducting THM simulations of the bentonite buffer.
The DNN-SWRC model incorporates temperature as an additional input variable,
allowing it to learn the relationship between suction and degree of saturation
under the general non-isothermal condition, which is difficult to represent
using a phenomenological SWRC. For effective modeling of the tank-scale test,
new axisymmetric Reproducing Kernel basis functions enriched with singular
Dirichlet enforcement representing heater placement and an effective convective
heat transfer coefficient representing thin-layer composite tank construction
are developed. The proposed method is demonstrated through the modeling of a
tank-scale experiment involving a cylindrical layer of MX-80 bentonite exposed
to central heating.Comment: 51 pages, 19 figure
Investigating the Correlation between Force Output, Strains, and Pressure for Active Skeletal Muscle Contractions
Experimental observations suggest that the force output of the skeletal
muscle tissue can be correlated to the intra-muscular pressure generated by the
muscle belly. However, pressure often proves difficult to measure through
in-vivo tests. Simulations on the other hand, offer a tool to model muscle
contractions and analyze the relationship between muscle force generation and
deformations as well as pressure outputs, enabling us to gain insight into
correlations among experimentally measurable quantities such as principal and
volumetric strains, and the force output. In this work, a correlation study is
performed using Pearson's and Spearman's correlation coefficients on the force
output of the skeletal muscle, the principal and volumetric strains experienced
by the muscle and the pressure developed within the muscle belly as the muscle
tissue undergoes isometric contractions due to varying activation profiles. The
study reveals strong correlations between force output and the strains at all
locations of the belly, irrespective of the type of activation profile used.
This observation enables estimation on the contribution of various muscle
groups to the total force by the experimentally measurable principal and
volumetric strains in the muscle belly. It is also observed that pressure does
not correlate well with force output due to stress relaxation near the boundary
of muscle belly
Noise reduction of plenum windows on the façade of a high-rise residential building next to heavy road traffic
Extensive traffic noise transmission loss measurements were carried out inside selected residential units of a standalone 32-storey housing block located next to a very busy and noisy main trunk road in the present study. A total of 35 units, which were all equipped with plenum windows, was surveyed. These plenum windows are intended to help reduce noise exposure of the residents and at the same time allow for a reasonable level of natural ventilation. The results show that the traffic noise transmission losses of the unit façades installed with the plenum windows adopted in this housing block vary between 10.6 and 13.0 dBA and are only weakly dependent on elevation from the trunk road. The results also validate in-situ the prediction model established previously by the authors using laboratory and site mockup data. Generalized models for both empirical and experimental estimation of the traffic noise transmission loss across a residential flat unit façade installed with multiple plenum windows are developed. The differences between their estimations are well within engineering tolerance
Urolithiasis location and size and the association with microhematuria and stone-related symptoms.
PURPOSE: To conduct a study to assess the association between calculus location and size and the incidence of both microhematuria and symptoms of urolithiasis in a urology office environment.
PATIENTS AND METHODS: After Institutional Review Board approval, a prospective study was conducted with data from 100 consecutive patients who presented to our office with documented urolithiasis. The location (caliceal, pelvic, or ureteral) and size (
RESULTS: A total of 111 stones were found in the study population resulting in a 45.9% incidence of microhematuria. In patients with renal pelvic and ureteral stones, 67.6% demonstrated microhematuria vs 36.4% with caliceal stones, P=0.0035. For stones ≥ 8 mm, 62.5% were positive for microhematuria vs 29.1% of stones \u3c8 \u3emm, P=0.0006. Ureteral or renal pelvic stones caused the most symptoms (70.6%) compared with caliceal stones (16.9%), P=0.0001. In those patients who reported pain associated with urolithiasis, 65.6% had concomitant microhematuria vs 36.8% in those without pain, P=0.0097.
CONCLUSIONS: Urinary calculus location and size are associated with the incidence of microhematuria and stone-related symptoms. Pain related to urolithiasis may be a positive predictor for the presence of microhematuria
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