178 research outputs found
A plug-and-play ripple mitigation approach for DC-links in hybrid systems
© 2016 IEEE.In this paper, a plug-and-play ripple mitigation technique is proposed. It requires only the sensing of the DC-link voltage and can operate fully independently to remove the low-frequency voltage ripple. The proposed technique is nonintrusive to the existing hardware and enables hot-swap operation without disrupting the normal functionality of the existing power system. It is user-friendly, modular and suitable for plug-and-play operation. The experimental results demonstrate the effectiveness of the ripple-mitigation capability of the proposed device. The DC-link voltage ripple in a 110 W miniature hybrid system comprising an AC/DC converter and two resistive loads is shown to be significantly reduced from 61 V to only 3.3 V. Moreover, it is shown that with the proposed device, the system reliability has been improved by alleviating the components' thermal stresses
Context-Aware Transformer for 3D Point Cloud Automatic Annotation
3D automatic annotation has received increased attention since manually
annotating 3D point clouds is laborious. However, existing methods are usually
complicated, e.g., pipelined training for 3D foreground/background
segmentation, cylindrical object proposals, and point completion. Furthermore,
they often overlook the inter-object feature relation that is particularly
informative to hard samples for 3D annotation. To this end, we propose a simple
yet effective end-to-end Context-Aware Transformer (CAT) as an automated 3D-box
labeler to generate precise 3D box annotations from 2D boxes, trained with a
small number of human annotations. We adopt the general encoder-decoder
architecture, where the CAT encoder consists of an intra-object encoder (local)
and an inter-object encoder (global), performing self-attention along the
sequence and batch dimensions, respectively. The former models intra-object
interactions among points, and the latter extracts feature relations among
different objects, thus boosting scene-level understanding. Via local and
global encoders, CAT can generate high-quality 3D box annotations with a
streamlined workflow, allowing it to outperform existing state-of-the-art by up
to 1.79% 3D AP on the hard task of the KITTI test set
Transcriptome profile of the human endothelial cell response to high- and low-density infections of Candida albicans
Background:
Candida albicans morphology switching and quorum-sensing are important factors for pathogenicity and virulence in persons with a compromised or deficient immune system. This study investigates the in vitro response of human umbilical vein endothelial cells (HUVECs) to infections with low and high densities of C. albicans. We hypothesize that higher cell densities of C. albicans yeast-form cells (blastospores), are more detrimental to HUVECs than lower cell densities of hyphal forms.
Methods:
Three biological replicates of confluent HUVECs in 6-well plates were challenged with 106 C. albicans blastospores (low-density infection) and 5 x 107 blastospores (highdensity infection) for 8 hours. The low-density infection generated true hyphae, but in the high-density infection, C. albicans remained as blastospores. RNA from these samples were subjected to DNA microarray transcript profiling. For MTT and XTT cell proliferation assays, conditioned media from the co-cultures for microarray experiments were incubated with HUVECs in 96-well plates for 24 hours.
Results:
The high-density blastospore-HUVEC co-cultures elicited significantly higher differential expression of genes involved in functional pathways of apoptosis, immune response, cell-cell signaling and cancer development, such as ZC3HAV1, HES1, CSF2, CXCL2 and PIM1, compared to the low-density true hyphae-HUVEC co-cultures. Cell proliferation assays also show that HUVECs incubated with conditioned media from the highdensity infection caused a higher percentage of cell death compared to incubation with conditioned media from the low-density infection. These results suggest that high densities of unattenuated, innate C. albicans blastospore cells can cause significant cellular toxicity, even though the cells are in the yeast form, not filamentous.
Conclusion:
Transcript profiling of this in vitro endothelial cell model may provide new insights into how C. albicans cell densities affect the host during the colonization and invasion through the bloodstream to the deep organs. We also suggest that quorum-sensing molecules and other unknown secretions from high-density C. albicans infections are strong inducers of cellular injury leading to cell death in systemic candidiasis
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