209 research outputs found
An Alarm Method for a Loose Parts Monitoring System
In order to reduce the false alarm rate and missed detection rate of a Loose Parts Monitoring System (LPMS) for Nuclear Power Plants, a new hybrid method combining Linear Predictive Coding (LPC) and Support Vector Machine (SVM) together to discriminate the loose part signal is proposed. The alarm process is divided into two stages. The first stage is to detect the weak burst signal for reducing the missed detection rate. Signal is whitened to improve the SNR, and then the weak burst signal can be detected by checking the short-term Root Mean Square (RMS) of the whitened signal. The second stage is to identify the detected burst signal for reducing the false alarm rate. Taking the signal's LPC coefficients as its characteristics, SVM is then utilized to determine whether the signal is generated by the impact of a loose part. The experiment shows that whitening the signal in the first stage can detect a loose part burst signal even at very low SNR and thusly can significantly reduce the rate of missed detection. In the second alarm stage, the loose parts' burst signal can be distinguished from pulse disturbance by using SVM. Even when the SNR is −15 dB, the system can still achieve a 100% recognition rat
Effects of Qijin granules on high glucose-induced proliferation, apoptosis and expression of nuclear factor- κB and MCP-1 in rat glomerular mesangial cells
Purpose: To investigate the effects of Qijin granules on high glucose-induced proliferation and apoptosis in rat glomerular mesangial cells (MC).Methods: MC cells from rats were passaged and cultured, and randomly divided into control group (CNG), high glucose group (HGG), Western medicine group (WMG, high glucose + Benazepril + Gliquidone), and Qijin granules 1/2/3 group (high glucose + different doses of Qijin granules). Mesangial cells proliferation was measured using MTT assay. The NF-κB, MCP-1 and inflammatory factors in supernatant were determined by ELISA. Apoptosis rate and cell cycle were assessed by flow cytometry. The apoptosis-related TGF-β1/Smad signaling pathway-related protein expressions were measured by Western blot.Results: The A-value and early apoptosis rate, apoptosis rate and S-phase percentage, and protein expressions of NF-κB, MCP-1, IL-6, IL-2, TNF-ɑ, Bax, Cyt-C, caspase-3, TGF-β1, and p-Smad3 of MC cells in the HGG at 12 h, 24 h and 48 h were higher than those in the CNG. The above indices were lower in the WMG, and Qijin granules 1/2/3 groups than in the HGG. The Bcl-2, Smad7 protein expression level and the percentage of G1 and G2/M phase were lower in the HGG than in the CNG, and the above indeices were higher in the WMG and Qijin granules 1/2/3 group than in HGG.Conclusion: Qijin granules can dose-dependently inhibit high glucose-induced proliferation and apoptosis in rat MC cells, block the cell cycle and reduce inflammatory responses. This may be related to the regulation of NF-κB, MCP-1 and TGF-β1/Smad signaling pathways. These findings provide theoretical and experimental basis for the clinical treatment of early diabetic nephropathy
A Communication Theory Perspective on Prompting Engineering Methods for Large Language Models
The springing up of Large Language Models (LLMs) has shifted the community
from single-task-orientated natural language processing (NLP) research to a
holistic end-to-end multi-task learning paradigm. Along this line of research
endeavors in the area, LLM-based prompting methods have attracted much
attention, partially due to the technological advantages brought by prompt
engineering (PE) as well as the underlying NLP principles disclosed by various
prompting methods. Traditional supervised learning usually requires training a
model based on labeled data and then making predictions. In contrast, PE
methods directly use the powerful capabilities of existing LLMs (i.e., GPT-3
and GPT-4) via composing appropriate prompts, especially under few-shot or
zero-shot scenarios. Facing the abundance of studies related to the prompting
and the ever-evolving nature of this field, this article aims to (i) illustrate
a novel perspective to review existing PE methods, within the well-established
communication theory framework; (ii) facilitate a better/deeper understanding
of developing trends of existing PE methods used in four typical tasks; (iii)
shed light on promising research directions for future PE methods
VibHead: An Authentication Scheme for Smart Headsets through Vibration
Recent years have witnessed the fast penetration of Virtual Reality (VR) and
Augmented Reality (AR) systems into our daily life, the security and privacy
issues of the VR/AR applications have been attracting considerable attention.
Most VR/AR systems adopt head-mounted devices (i.e., smart headsets) to
interact with users and the devices usually store the users' private data.
Hence, authentication schemes are desired for the head-mounted devices.
Traditional knowledge-based authentication schemes for general personal devices
have been proved vulnerable to shoulder-surfing attacks, especially considering
the headsets may block the sight of the users. Although the robustness of the
knowledge-based authentication can be improved by designing complicated secret
codes in virtual space, this approach induces a compromise of usability.
Another choice is to leverage the users' biometrics; however, it either relies
on highly advanced equipments which may not always be available in commercial
headsets or introduce heavy cognitive load to users.
In this paper, we propose a vibration-based authentication scheme, VibHead,
for smart headsets. Since the propagation of vibration signals through human
heads presents unique patterns for different individuals, VibHead employs a
CNN-based model to classify registered legitimate users based the features
extracted from the vibration signals. We also design a two-step authentication
scheme where the above user classifiers are utilized to distinguish the
legitimate user from illegitimate ones. We implement VibHead on a Microsoft
HoloLens equipped with a linear motor and an IMU sensor which are commonly used
in off-the-shelf personal smart devices. According to the results of our
extensive experiments, with short vibration signals (), VibHead has an
outstanding authentication accuracy; both FAR and FRR are around 5%
Exploring Gut Microbiota in Patients with Colorectal Disease Based on 16S rRNA Gene Amplicon and Shallow Metagenomic Sequencing
The gastrointestinal tract, the largest human microbial reservoir, is highly dynamic. The gut microbes play essential roles in causing colorectal diseases. In the present study, we explored potential keystone taxa during the development of colorectal diseases in central China. Fecal samples of some patients were collected and were allocated to the adenoma (Group A), colorectal cancer (Group C), and hemorrhoid (Group H) groups. The 16S rRNA amplicon and shallow metagenomic sequencing (SMS) strategies were used to recover the gut microbiota. Microbial diversities obtained from 16S rRNA amplicon and SMS data were similar. Group C had the highest diversity, although no significant difference in diversity was observed among the groups. The most dominant phyla in the gut microbiota of patients with colorectal diseases were Bacteroidetes, Firmicutes, and Proteobacteria, accounting for >95% of microbes in the samples. The most abundant genera in the samples were Bacteroides, Prevotella, and Escherichia/Shigella, and further species-level and network analyses identified certain potential keystone taxa in each group. Some of the dominant species, such as Prevotella copri, Bacteroides dorei, and Bacteroides vulgatus, could be responsible for causing colorectal diseases. The SMS data recovered diverse antibiotic resistance genes of tetracycline, macrolide, and beta-lactam, which could be a result of antibiotic overuse. This study explored the gut microbiota of patients with three different types of colorectal diseases, and the microbial diversity results obtained from 16S rRNA amplicon sequencing and SMS data were found to be similar. However, the findings of this study are based on a limited sample size, which warrants further large-scale studies. The recovery of gut microbiota profiles in patients with colorectal diseases could be beneficial for future diagnosis and treatment with modulation of the gut microbiota. Moreover, SMS data can provide accurate species- and gene-level information, and it is economical. It can therefore be widely applied in future clinical metagenomic studies
Multi-wavelength Stellar Polarimetry of the Filamentary Cloud IC5146: I. Dust Properties
We present optical and near-infrared stellar polarization observations toward
the dark filamentary clouds associated with IC5146. The data allow us to
investigate the dust properties (this paper) and the magnetic field structure
(Paper II). A total of 2022 background stars were detected in -, -,
-, and/or -bands to mag. The ratio of the polarization
percentage at different wavelengths provides an estimate of ,
the wavelength of peak polarization, which is an indicator of the small-size
cutoff of the grain size distribution. The grain size distribution seems to
significantly change at 3 mag, where both the average and dispersion
of decrease. In addition, we found
0.6-0.9 m for mag, which is larger than the 0.55 m
in the general ISM, suggesting that grain growth has already started in low
regions. Our data also reveal that polarization efficiency (PE ) decreases with as a power-law in -, -, and
-bands with indices of -0.710.10, -1.230.10 and -0.530.09.
However, -band data show a power index change; the PE varies with
steeply (index of -0.950.30) when mag but softly
(index of -0.250.06) for greater values. The soft decay of PE in
high regions is consistent with the Radiative Aligned Torque model,
suggesting that our data trace the magnetic field to mag.
Furthermore, the breakpoint found in -band is similar to the where we
found the dispersion significantly decreased. Therefore, the
flat PE- in high regions implies that the power index changes result
from additional grain growth.Comment: 31 pages, 17 figures, and 3 tables; accepted for publication in Ap
Applications and Perspectives of Cascade Reactions in Bacterial Infection Control
Cascade reactions integrate two or more reactions, of which each subsequent reaction can only start when the previous reaction step is completed. Employing natural substrates in the human body such as glucose and oxygen, cascade reactions can generate reactive oxygen species (ROS) to kill tumor cells, but cascade reactions may also have potential as a direly needed, novel bacterial infection-control strategy. ROS can disintegrate the EPS matrix of infectious biofilm, disrupt bacterial cell membranes, and damage intra-cellular DNA. Application of cascade reactions producing ROS as a new infection-control strategy is still in its infancy. The main advantages for infection-control cascade reactions include the fact that they are non-antibiotic based and induction of ROS resistance is unlikely. However, the amount of ROS generated is generally low and antimicrobial efficacies reported are still far <3-4 log units necessary for clinical efficacy. Increasing the amounts of ROS generated by adding more substrate bears the risk of collateral damage to tissue surrounding an infection site. Collateral tissue damage upon increasing substrate concentrations may be prevented by locally increasing substrate concentrations, for instance, using smart nanocarriers. Smart, pH-responsive nanocarriers can self-target and accumulate in infectious biofilms from the blood circulation to confine ROS production inside the biofilm to yield long-term presence of ROS, despite the short lifetime (nanoseconds) of individual ROS molecules. Increasing bacterial killing efficacies using cascade reaction components containing nanocarriers constitutes a first, major challenge in the development of infection-control cascade reactions. Nevertheless, their use in combination with clinical antibiotic treatment may already yield synergistic effects, but this remains to be established for cascade reactions. Furthermore, specific patient groups possessing elevated levels of endogenous substrate (for instance, diabetic or cancer patients) may benefit from the use of cascade reaction components containing nanocarriers
Composition and biological activity of tea polysaccharides obtained by water extraction and enzymatic extraction
The composition and biological activities of tea polysaccharides (TPS) obtained by traditional water extraction, boiling water extraction and enzymatic extraction were investigated. Boiling water extraction (100 °C for 2 h) was found to be the optimal method with higher yield of TPS (1.91%) consisting of higher contents of neutral saccharides (57.82%) and acid saccharides (26.95%) with lowest protein content (3.06%). TPS obtained by boiling water extraction exhibited a strong inhibitory effect on α-glucosidase with the inhibitory rate of 86.67%. The inhibitory effect of TPS on α-glucosidase increased with increasing neutral polysaccharides content in TPS. TPS obtained by boiling water extraction (50 μg/mL) had very strong proliferation effect on lymphocyte.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Optical vortices enabled by structural vortices
The structural symmetry of solids plays an important role in defining their
linear and nonlinear optical properties. The quest for versatile,
cost-effective, large-scale, and defect-free approaches and materials platforms
for tailoring structural and optical properties on demand has been underway for
decades. We experimentally demonstrate a bottom-up self-assembly-based organic
engineered material comprised of synthesized molecules with large dipole
moments that are crystallized into a spherulite structure. The molecules align
in an azimuthal direction, resulting in a vortex polarity with spontaneously
broken symmetry leading to strong optical anisotropy and nonlinear optical
responses. These unique polarization properties of the judiciously designed
organic spherulite combined with the symmetry of structured optical beams
enable a plethora of new linear and nonlinear light-matter interactions,
including the generation of optical vortex beams with complex spin states and
on-demand topological charges at the fundamental, doubled, and tripled
frequencies. The results of this work are likely to enable numerous
applications in areas such as high-dimensional quantum information processing,
with large capacity and high security. The demonstrated spherulite crystals
facilitate stand-alone micro-scale devices that rely on the unique micro-scale
spontaneous vortex polarity that is likely to enable future applications for
high-dimensional quantum information processing, spatiotemporal optical
vortices, and a novel platform for optical manipulation and trapping
- …