4,024 research outputs found
Driving Control Technologies of New High-Efficient Motors
Although switched-reluctance machine (SRM) possesses many structural advantages and application potential, it is rather difficult to successfully control with high performance being comparable to other machines. Many critical affairs must be properly treated to obtain the improved operating characteristics. This chapter presents the basic and key technologies of switched-reluctance machine in motor and generator operations. The contents in this chapter include: (1) structures and governing equations of SRM; (2) some commonly used SRM converters; (3) estimation of key parameters and performance evaluation of SRM drive; (4) commutation scheme, current control scheme, and speed control scheme of SRM drive; (5) some commonly used front-end converters and their operation controls for SRM drive; (6) reversible and regenerative braking operation controls for SRM drive; (7) some tuning issues for SRM drive; (8) operation control and some tuning issues of switched-reluctance generators; and (9) experimental application exploration for SRM systems: (a) wind generator and microgrid; (b) EV SRM drive
Rethinking Backdoor Attacks on Dataset Distillation: A Kernel Method Perspective
Dataset distillation offers a potential means to enhance data efficiency in
deep learning. Recent studies have shown its ability to counteract backdoor
risks present in original training samples. In this study, we delve into the
theoretical aspects of backdoor attacks and dataset distillation based on
kernel methods. We introduce two new theory-driven trigger pattern generation
methods specialized for dataset distillation. Following a comprehensive set of
analyses and experiments, we show that our optimization-based trigger design
framework informs effective backdoor attacks on dataset distillation. Notably,
datasets poisoned by our designed trigger prove resilient against conventional
backdoor attack detection and mitigation methods. Our empirical results
validate that the triggers developed using our approaches are proficient at
executing resilient backdoor attacks.Comment: 19 pages, 4 figure
Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis
BACKGROUND: CAP/Capulet (Capt), Slingshot (Ssh) and Cofilin/Twinstar (Tsr) are actin-binding proteins that restrict actin polymerization. Previously, it was shown that low resolution analyses of loss-of-function mutations in capt, ssh and tsr all show ectopic F-actin accumulation in various Drosophila tissues. In contrast, RNAi depletion of capt, tsr and ssh in Drosophila S2 cells all affect actin-based lamella formation differently. Whether loss of these three related genes might cause the same effect in the same tissue remains unclear. METHODS: Loss-of-function mutant clones were generated using the MARCM or EGUF system whereas overexpression clones were generated using the Flip-out system. Immunostaining were then performed in eye imaginal discs with clones. FRAP was performed in cultured eye discs. RESULTS: Here, we compared their loss-of-function phenotype at single-cell resolution, using a sheet of epithelial cells in the Drosophila eye imaginal disc as a model system. Surprisingly, we found that capt and ssh, but not tsr, mutant cells within and posterior to the morphogenetic furrow (MF) shared similar phenotypes. The capt/ssh mutant cells possessed: (1) hexagonal cell packing with discontinuous adherens junctions; and (2) largely complementary accumulation of excessive phosphorylated myosin light chain (p-MLC) and F-actin rings at the apical cortex. We further showed that the capt/ssh mutant phenotypes depended on the inactivation of protein kinase A (PKA) and activation of Rho. CONCLUSIONS: Although Capt, Ssh and Tsr were reported to negatively regulate actin polymerization, we found that Capt and Ssh, but not Tsr, share overlapping functions during eye morphogenesis
Discordant Findings of Skeletal Metastasis Between Tc99m MDP Bone Scans and F18 FDG PET/CT Imaging for Advanced Breast and Lung Cancers—Two Case Reports and Literature Review
Traditionally, Tc99m methyl diphosphate (MDP) bone scintigraphy provides high-sensitivity detection of skeletal metastasis from breast and lung cancers in regular follow-up. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), based on the glucose metabolism of malignant cells, plays a role in describing rumor growth, proliferation of neoplasm and the extent of metastasis. In general, concordant findings of skeletal metastasis are seen on both types of image, especially in cases of breast and lung cancer. However, there were extremely discordant findings of skeletal metastasis between bone scans and F18 FDG PET/CT imaging in two cases among 300 consecutive F18 FDG PET/CT follow-up exams of patients with malignancies, during the past year, in our center. Both cases, one of breast cancer and one of lung cancer, had negative bone scintigraphic findings, but a diffusely high grade of F18 FDG avid marrow infiltration in the axial spine, leading to the diagnosis of stage IV disease in both cases. Owing to variant genetic aberrance of malignance, F18 FDG PET/CT reveals direct evidence of diffuse, rapid neoplasm metabolism in the bone marrow of the spine, but not of secondary osteoblastic reactions in vivo. F18 FDG PET/CT should always be employed in the follow-up of patients with malignancies
Changes in corneal curvature after wearing the orthokeratology lens
AbstractIntroductionThe orthokeratology lens (OK lens) is designed to reshape the cornea and correct refraction error. Owing to the convenience of ceasing the use of glasses during the day, the use of the OK lens is increasing in myopic children. In this study, changes in corneal curvature and astigmatism after wearing the OK lens were analyzed.MethodsThis retrospective cohort study included 65 children (130 eyes) who underwent full and regular examinations. None of the participants had any ocular disease other than myopia and astigmatism. The OK lenses used in this study were four-zone, reverse-geometry lenses. The corneal curvature of each patient was checked annually after the patients discontinued daily wearing of the OK lens for 10 days. Student t test and repeated measures analysis of variance (ANOVA) analyses were performed to compare the results.ResultsThe radius of corneal curvature showed a progressive annual increase with significant differences, both in the steepest and flattest radius of the corneal curvature (p < 0.001 and p = 0.001, respectively). The mean radius of the steepest and flattest corneal curvature increased significantly from baseline to the following years consecutively (all p < 0.001). Nevertheless, astigmatism did not change significantly in any of the tests.ConclusionCorneal curvature changed as the patients grew older. There was a statistically significant increase in the radius of the corneal curvature in the myopic children studied. For correct fit of OK lenses, the radius of the corneal curvature should be regularly checked prior to dispensing a new set of lenses
Therapeutic Effect of C-Phycocyanin Extracted from Blue Green Algae in a Rat Model of Acute Lung Injury Induced by Lipopolysaccharide
C-Phycocyanin (CPC), extracted from blue green algae, is a dietary nutritional supplement due to its several beneficial pharmacological effects. This study was conducted to evaluate whether CPC protects against lipopolysaccharide- (LPS-) induced acute lung injury (ALI) in rats. Rats were challenged with LPS (5 mg/kg body weight) intratracheally to induce ALI. After 3 h LPS instillation, rats were administrated with CPC (50 mg/kg body weight, i.p.) for another 3 h. Our results showed that posttreatment with CPC significantly inhibited LPS-induced elevation of protein concentration, nitrite/nitrate level, release of proinflammatory cytokines, the number of total polymorphonuclear cells in bronchoalveolar lavage fluid, and lung edema evidenced by decrease of lung wet/dry weight ratio accompanied by a remarkable improvement of lung histopathological alterations. Furthermore, CPC significantly attenuated LPS-induced myeloperoxidase activity, O2− formation, expression of inducible nitric oxide synthase, and cyclooxygenase-2 as well as nuclear factor-kappa B (NF-κB) activation in lungs. Additionally, CPC significantly downregulated proapoptotic proteins such as caspase-3 and Bax, but upregulated antiapoptotic proteins such as Bcl-2 and Bcl-XL in lungs exposed to LPS. These findings indicate that CPC could be potentially useful for treatment of LPS-related ALI by inhibiting inflammatory responses and apoptosis in lung tissues
New primers for methylation-specific polymerase chain reaction enhance specificity of detecting STAT1 methylation
AbstractObjectiveSignal transducer and activator of transcription (STAT)1 is a key tumor suppressor, which is always methylated in a variety of human cancers. However, nonspecific primers for the detection of specific promoter hypermethylation of STAT1 gene can lead to false-positive or false-negative results for gene methylation.Materials and MethodsWe designed new primers for the detection of STAT1 methylation and compared the sensitivities and specificities of these new primers with prior published primers by methylation-specific polymerase chain reaction (PCR) from ovarian clear cell carcinomas. The mRNA expression levels of STAT1 in these cancerous tissues were also evaluated by reverse-transcriptase PCR and correlated with the results of promoter methylation of STAT1 gene.ResultsNine (39%) of the 23 samples detected by the new primers and 13 samples (56%) detected by prior published primers showed STAT1 methylation. A direct DNA sequencing test revealed that four of the 13 samples (30.8%) showed false positivity for STAT1 methylation using the prior published primers. In contrast, none of the nine samples was false-positive for the detection of STAT1 methylation using the new primers. The new primers for the detection of STAT1 methylation showed 100% specificity and 100% sensitivity without false positivity.ConclusionSpecific primers for methylation-specific PCR are mandatory for the accurate detection of STAT1 gene methylation. Besides, specific primers can generate correct interpretation of STAT1 gene methylation, and its correlation with the clinicopathological characteristics and outcome of cancer patients
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