214 research outputs found
Score-based Generative Modeling Secretly Minimizes the Wasserstein Distance
Score-based generative models are shown to achieve remarkable empirical
performances in various applications such as image generation and audio
synthesis. However, a theoretical understanding of score-based diffusion models
is still incomplete. Recently, Song et al. showed that the training objective
of score-based generative models is equivalent to minimizing the
Kullback-Leibler divergence of the generated distribution from the data
distribution. In this work, we show that score-based models also minimize the
Wasserstein distance between them under suitable assumptions on the model.
Specifically, we prove that the Wasserstein distance is upper bounded by the
square root of the objective function up to multiplicative constants and a
fixed constant offset. Our proof is based on a novel application of the theory
of optimal transport, which can be of independent interest to the society. Our
numerical experiments support our findings. By analyzing our upper bounds, we
provide a few techniques to obtain tighter upper bounds
Deep Residual CNN for Multi-Class Chest Infection Diagnosis
The advent of deep learning has significantly propelled the capabilities of
automated medical image diagnosis, providing valuable tools and resources in
the realm of healthcare and medical diagnostics. This research delves into the
development and evaluation of a Deep Residual Convolutional Neural Network
(CNN) for the multi-class diagnosis of chest infections, utilizing chest X-ray
images. The implemented model, trained and validated on a dataset amalgamated
from diverse sources, demonstrated a robust overall accuracy of 93%. However,
nuanced disparities in performance across different classes, particularly
Fibrosis, underscored the complexity and challenges inherent in automated
medical image diagnosis. The insights derived pave the way for future research,
focusing on enhancing the model's proficiency in classifying conditions that
present more subtle and nuanced visual features in the images, as well as
optimizing and refining the model architecture and training process. This paper
provides a comprehensive exploration into the development, implementation, and
evaluation of the model, offering insights and directions for future research
and development in the field
User Recognition Based on Human Body Impulse Response: A Feasibility Study
Human recognition technologies for security systems require high reliability and easy accessibility in the advent of the internet of things (IoT). While several biometric approaches have been studied for user recognition, there are demands for more convenient techniques suitable for the IoT devices. Recently, electrical frequency responses of the human body have been unveiled as one of promising biometric signals, but the pilot studies are inconclusive about the characteristics of human body as a transmission medium for electric signals. This paper provides a multi-domain analysis of human body impulse responses (HBIR) measured at the receiver when customized impulse signals are passed through the human body. We analyzed the impulse responses in the time, frequency, and wavelet domains and extracted representative feature vectors using a proposed accumulated difference metric in each domain. The classification performance was tested using the k-nearest neighbors (KNN) algorithm and the support vector machine (SVM) algorithm on 10-day data acquired from five subjects. The average classification accuracies of the simple classifier KNN for the time, frequency, and wavelet features reached 92.99%, 77.01%, and 94.55%, respectively. In addition, the kernel-based SVM slightly improved the accuracies of three features by 0.58%, 2.34%, and 0.42%, respectively. The result shows potential of the proposed approach for user recognition based on HBIR
Glycogen synthase kinase 3 beta suppresses polyglutamine aggregation by inhibiting Vaccinia-related kinase 2 activity
Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal expansion of polyglutamine repeats in the N-terminal of huntingtin. The amount of aggregate-prone protein is controlled by various mechanisms, including molecular chaperones. Vaccinia-related kinase 2 (VRK2) is known to negatively regulate chaperonin TRiC, and VRK2-facilitated degradation of TRiC increases polyQ protein aggregation, which is involved in HD. We found that VRK2 activity was negatively controlled by glycogen synthase kinase 3 beta (GSK3 beta). GSK3 beta directly bound to VRK2 and inhibited the catalytic activity of VRK2 in a kinase activity-independent manner. Furthermore, GSK3 beta increased the stability of TRiC and decreased the formation of HttQ103-GFP aggregates by inhibiting VRK2. These results indicate that GSK3 beta signaling may be a regulatory mechanism of HD progression and suggest targets for further therapeutic trials for HD.1131Ysciescopu
Associations Among the Opioid Receptor Gene (OPRM1) A118G Polymorphism, Psychiatric Symptoms, and Quantitative EEG in Korean Males with Gambling Disorder: A Pilot Study
Background and aims: A single nucleotide polymorphism of A118G (SNP; rs1799971) in the opioid receptor μ-1 (OPRM1) gene is a missense variant that influences the affinity of μ-opioid receptors. This study aimed to investigate the associations among the A118G polymorphism in the OPRM1 gene, psychiatric symptoms, and quantitative electroencephalography (qEEG) findings in patients with gambling disorder. Methods: Fifty-five male patients with gambling disorder aged between 18 and 65 years old participated in the study. The A118G polymorphism was genotyped into the AA, GA, and GG groups by the polymerase chain reaction/restriction fragment length polymorphism method. Resting-state qEEG was recorded with the eyes closed, and the absolute power of the delta (1–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz) frequency bands was analyzed. Psychiatric symptoms, including depression, anxiety, impulsivity and severity of gambling, were assessed by a self-rating scale. Results: There were no significant differences in psychiatric symptoms among the three genotype groups (AA, GA, and GG). However, the frequency band power of qEEG showed significant differences among the three genotype groups. The absolute power of the beta and theta bands in the frontal lobe was higher in G allele carriers. Discussion and conclusion: Based on the findings of this study, the polymorphism in the OPRM1 gene might affect the neurophysiological process in patients with gambling disorder
Metal-organic frameworks constructed from flexible ditopic ligands: Conformational diversity of an aliphatic ligand
The solvothermal reaction of adipic acid as a flexible ditopic ligand and the metal ions MnII, CoII, and TbIII afforded three novel metal-organic frameworks (MOFs), {[Mn2(adipate) 2(DMA)]} (1), {[Co2(adipate)2(DMF)] ??1DMF??1.5H2O} (2), and {[Tb3(adipate) 4.5(DMF)2]} (3) (DMA = N,N-dimethylacetamide; DMF = N,N-dimethylformamide), respectively, which were structurally characterized by single-crystal X-ray diffraction. Depending on the kind of metal ion and solvent system, the conformations and coordination modes of the adipate ligands were diverse and governed the entire MOF structure. Compound 1 consists of the secondary building units (SBUs) of Mn-O chains that were linked by adipate ligands extending in two-dimensional sheets, which were infinitely stacked in a layer-by-layer manner. Compound 2 presented a three-dimensional MOF constructed from Co-O chains and bridging adipate ligands extending in four different directions. Compound 3 also had a three-dimensional structure which was formed by Tb-O chains connected with adipate ligands in six directions. From these structures, ten different adipate ligands with diverse conformations were found, and the potential energy of each conformation was calculated by the first-principles density function. In addition, the luminescence properties of the Tb-based MOF 3 were investigated in the solid state at room temperature.close0
Autism-like behavior caused by deletion of vaccinia-related kinase 3 is improved by TrkB stimulation
Vaccinia-related kinases (VRKs) are multifaceted serine/threonine kinases that play essential roles in various aspects of cell signaling, cell cycle progression, apoptosis, and neuronal development and differentiation. However, the neuronal function of VRK3 is still unknown despite its etiological potential in human autism spectrum disorder (ASD). Here, we report that VRK3-deficient mice exhibit typical symptoms of autism-like behavior, including hyperactivity, stereotyped behaviors, reduced social interaction, and impaired context-dependent spatial memory. A significant decrease in dendritic spine number and arborization were identified in the hippocampus CA1 of VRK3-deficient mice. These mice also exhibited a reduced rectification of AMPA receptor-mediated current and changes in expression of synaptic and signaling proteins, including tyrosine receptor kinase B (TrkB), Arc, and CaMKII alpha. Notably, TrkB stimulation with 7,8-dihydroxyflavone reversed the altered synaptic structure and function and successfully restored autism-like behavior in VRK3-deficient mice. These results reveal that VRK3 plays a critical role in neurodevelopmental disorders and suggest a potential therapeutic strategy for ASD.112Ysciescopu
FBXW7-mediated ERK3 degradation regulates the proliferation of lung cancer cells
Extracellular signal-regulated kinase 3 (ERK3) is an atypical member of the mitogen-activated protein kinase (MAPK) family, members of which play essential roles in diverse cellular processes during carcinogenesis, including cell proliferation, differentiation, migration, and invasion. Unlike other MAPKs, ERK3 is an unstable protein with a short half-life. Although deubiquitination of ERK3 has been suggested to regulate the activity, its ubiquitination has not been described in the literature. Here, we report that FBXW7 (F-box and WD repeat domain-containing 7) acts as a ubiquitination E3 ligase for ERK3. Mammalian two-hybrid assay and immunoprecipitation results demonstrated that ERK3 is a novel binding partner of FBXW7. Furthermore, complex formation between ERK3 and the S-phase kinase-associated protein 1 (SKP1)-cullin 1-F-box protein (SCF) E3 ligase resulted in the destabilization of ERK3 via a ubiquitination-mediated proteasomal degradation pathway, and FBXW7 depletion restored ERK3 protein levels by inhibiting this ubiquitination. The interaction between ERK3 and FBXW7 was driven by binding between the C34D of ERK3, especially at Thr417 and Thr421, and the WD40 domain of FBXW7. A double mutant of ERK3 (Thr417 and Thr421 to alanine) abrogated FBXW7-mediated ubiquitination. Importantly, ERK3 knockdown inhibited the proliferation of lung cancer cells by regulating the G1/S-phase transition of the cell cycle. These results show that FBXW7-mediated ERK3 destabilization suppresses lung cancer cell proliferation in vitro
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