469 research outputs found
Quantifying the Impact of Label Noise on Federated Learning
Federated Learning (FL) is a distributed machine learning paradigm where
clients collaboratively train a model using their local (human-generated)
datasets. While existing studies focus on FL algorithm development to tackle
data heterogeneity across clients, the important issue of data quality (e.g.,
label noise) in FL is overlooked. This paper aims to fill this gap by providing
a quantitative study on the impact of label noise on FL. We derive an upper
bound for the generalization error that is linear in the clients' label noise
level. Then we conduct experiments on MNIST and CIFAR-10 datasets using various
FL algorithms. Our empirical results show that the global model accuracy
linearly decreases as the noise level increases, which is consistent with our
theoretical analysis. We further find that label noise slows down the
convergence of FL training, and the global model tends to overfit when the
noise level is high.Comment: Accepted by The AAAI 2023 Workshop on Representation Learning for
Responsible Human-Centric A
Anti-Apoptosis Effect of Astragaloside Iv on Alzheimer's Disease Rat Model via Enhancing the Expression of Bcl-2 And Bcl-Xl
The aim is to explore the protective effect of Astragaloside IV on Alzheimer’s disease (AD) in rats induced by amyloid-ß peptide (Aß1-42) and its potential therapeutic mechanism. Methods: 50 Male Sprague Dawley rats were divided into five groups (10 rats for each): control group, model group, treatment groups 1~3. 10μg Aß1-42 was injected bilaterally into the dorsal dentate gyrus of the hippocampus of rats in the model and treatment groups to prepare the AD models. 24h after modeling, Astragaloside IV administration, with different drug dosages of 20mg/(kg•day), 40mg/(kg•day) and 60mg/(kg•day), was performed by gastric perfusion for rats in the treatment group 1~3. Later on, the cognitive ability of rats was examined by a series of behavioral tests, and the expression of Bcl-2 and Bcl-xl in the hippocampus of rats was detected by the fluorescein based Quantitative RT-PCR. Results: The spontaneous alternation test in a Y maze and Morris water maze task have demonstrated that the repeated daily administration of Astragaloside IV at the doses of 20mg/kg bw/day) (p<0.05), 40mg/kg bw/day) (p<0.01), and 60mg/kg bw/day) (p<0.01) significantly ameliorated the impairment of performance caused by Aß1–42. Furthermore, Astragaloside IV also enhanced the expression of Bcl-2 and Bcl-xl in hippocampal neurons of rats in a dosage-dependent manner. Conclusion: These findings suggest that Astragaloside IV could alleviate cognitive impairment and enhance the expression of Bcl-2 and Bcl-xl in hippocampus of rat models with AD.
Simple filter microchip for rapid separation of plasma and viruses from whole blood
Sample preparation is a significant challenge for detection and sensing technologies, since the presence of blood cells can interfere with the accuracy and reliability of virus detection at the nanoscale for point-of-care testing. To the best of our knowledge, there is not an existing on-chip virus isolation technology that does not use complex fluidic pumps. Here, we presented a lab-on-a-chip filter device to isolate plasma and viruses from unprocessed whole blood based on size exclusion without using a micropump. We demonstrated that viruses (eg, HIV) can be separated on a filter-based chip (2-μm pore size) from HIV-spiked whole blood at high recovery efficiencies of 89.9% ± 5.0%, 80.5% ± 4.3%, and 78.2% ± 3.8%, for viral loads of 1000, 10,000 and 100,000 copies/mL, respectively. Meanwhile, 81.7% ± 6.7% of red blood cells and 89.5% ± 2.4% of white blood cells were retained on 2 μm pore–sized filter microchips. We also tested these filter microchips with seven HIV-infected patient samples and observed recovery efficiencies ranging from 73.1% ± 8.3% to 82.5% ± 4.1%. These results are first steps towards developing disposable point-of-care diagnostics and monitoring devices for resource-constrained settings, as well as hospital and primary care settings
Clinical characteristics and microbiota analysis of 44 patients with granulomatous mastitis
IntroductionGranulomatous mastitis (GM) is a chronic inflammatory breast disease. In recent years, the role of Corynebacterium in GM onset has received more and more attention. This study aims to detect the dominant bacterium in GM patients and analyze the association between clinical characteristics and infectious factors.MethodsIn this study, 88 samples from 44 GM patients, six acute lactation mastitis (ALM) patients, and 25 non-inflammatory breast disease (NIB) patients were divided into a GM pus group, a GM tissue group, an ALM pus group, and a NIB tissue group; then, 16S ribosomal DNA sequencing was used to explore their microbiota. The clinical data of all 44 GM patients were also retrospectively collected and analyzed to determine their relationship with infection.ResultsThe median age of the 44 GM patients was 33 years, and 88.6% of patients had primary-onset cases, while 11.4% were recurrences; additionally, 89.5% of patients were postpartum and 10.5% were nulliparous. The serum prolactin level was abnormal in nine patients (24.3%). Samples from 15 GM patients (34.1%) had a Corynebacterium abundance of >1% (1.08–80.08%), with eight (53.3%) displaying an abundance of >10%. Corynebacterium was the only genus with significant differences between the GM pus group and the other three groups (p < 0.05). Corynebacterium kroppenstedtii was the predominant Corynebacterium species. Among clinical characteristics, a statistical difference in breast abscess formation was observed according to Corynebacterium abundance in Corynebacterium-positive and- negative patients (p < 0.05).DiscussionThis study explored the relationship between Corynebacterium infection and GM, compared the clinical characteristics between Corynebacterium-positive and- negative patients, and provided support for the role of Corynebacterium species-in particular, C. kroppenstedtii-in the pathogenesis of GM. The detection of Corynebacterium can predict GM onset, especially in patients with high prolactin levels or a history of recent lactation
The performance of large-pitch AC-LGAD with different N+ dose
AC-Coupled LGAD (AC-LGAD) is a new 4D detector developed based on the Low
Gain Avalanche Diode (LGAD) technology, which can accurately measure the time
and spatial information of particles. Institute of High Energy Physics (IHEP)
designed a large-size AC-LGAD with a pitch of 2000 {\mu}m and AC pad of 1000
{\mu}m, and explored the effect of N+ layer dose on the spatial resolution and
time resolution. The spatial resolution varied from 32.7 {\mu}m to 15.1 {\mu}m
depending on N+ dose. The time resolution does not change significantly at
different N+ doses, which is about 15-17 ps. AC-LGAD with a low N+ dose has a
large attenuation factor and better spatial resolution. Large signal
attenuation factor and low noise level are beneficial to improve the spatial
resolution of the AC-LGAD sensor
Characterization of the response of IHEP-IME LGAD with shallow carbon to Gamma Irradiation
Low Gain Avalanche Detectors (LGAD), as part of High-Granularity Timing
Detector (HGTD), is crucial to reducing pileup in the upgrading to HL-LHC. Many
studies have been done on the bulk damages of the LGAD. However, there's no
study about the surface radiation hardness of the LGAD sensors with carbon
implanted. The IHEP-IME LGAD version 3 with the shallow carbon and different
interpad separations were irradiated up to 2 MGy by gamma irradiation. The
performance of the IHEP-IME LGAD version 3 before and after irradiation had
been tested, such as the leakage current, break-down voltage, capacitance,
V, and inter-pad resistance. The results showed that apart from minor
fluctuations in some samples, no significant changes concerning inter-pad
separation were observed before and after irradiation. Leakage current and
break-down voltage increase after irradiation, which is considered due to
surface passivation; the overall inter-pad resistance are larger than $10^9\
\Omega_{gl}$ after irradiation. All parameters meet the
requirements of HGTD, and the results indicated that IHEP-IME LGAD v3 has
excellent anti-irradiation performance
Characterisation of Spatial and Timing Resolution of IHEP AC-LGAD Strip
AC-coupled LGAD(AC-LGAD) Strip is a new design of LGAD that allows
high-precision detection of particle spatiotemporal information whereas
reducing the density of readout electronics. For AC-LGAD Strips, there is
limited research on the impact of different strip pitches on the spatiotemporal
detection performance at the small amount of injected charge. The Institute of
High Energy Physics has designed an AC-LGAD Strip prototype with pitches of 150
, 200 , and 250 . The spatial and timing resolutions of
the prototype are studied through the laser Transient Current Technique (TCT)
scan with different amounts of injected charge. The results show that both the
spatial and timing resolution improves as the strip pitch decreases. Increases
in both temporal and spatial resolutions as the amount of charge injected
increases are observed. The spatial and timing resolution is better than 60 ps
and 40 at 1 Minimum Ionizing Particle (MIP), and better than 10 ps and
5 at 40 MIPs. Increasing Signal-to-Noise Ratio (SNR) is the key to
improving spatial and temporal resolution, whereas increasing the signal
attenuation rate by reducing the gap between adjacent electrodes also helps to
improve spatial resolution. The enhancements of spatial and timing resolutions
by both SNR and signal attenuation rate decrease with increasing amount of MIP.
This study can help design and optimize the AC-LGAD Strip detectors and readout
electronics
A targetable nanogenerator of nitric oxide for light-triggered cytotoxicity
NSF China [21305116, 21272196, 21072162]; 973 program [2013CB933901]; PCSIRT; NFFTBS [J1310024]; Fundamental Research Funds for the Central Universities [2011121020]Nanoscale-vesicles that can target pathogens are valuable for biomedical applications. In this study, a photo-responsive nanogenerator of nitric oxide (NO) comprised of a hydrophobic core of 3trifluoromethyl- 4-nitroaniline (TFNA) and a hydrophilic shell of mannosylated poly[styrene-alter-(maleic acid)] was constructed to target and kill lectin-expressing cells. The release of NO from the nanogenerator (T@ P-M) was effectively induced by luminol-derived chemiluminescence (CL), leading to high-efficiency killing of Escherichia coli (E. coli) treated with T@ P-M. In addition, the uptake of T@ P-M by Raw 264.7 macrophages was achieved by cell surface lectin-mediated endocytosis, enabling the intracellular release of NO from the internalized T@ P-M upon the induction of extracellular chemiluminescence. Because in vivo-generated CL can overcome the limited penetration of exogenous light into biological tissues, T@ P-M has potential uses as a targetable photo-activatable microbicide to combat pathogens bearing lectins or residing in macrophages
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