Real-time GPU-based adaptive beamformer for high quality ultrasound imaging

Poster Session Session P1Aa. Beam Formation: Computational Aspects And Artifact Reduction: no. P1Ac-7A real-time adaptive minimum variance (MV) beam-former realized using graphics processing units (GPUs) is presented. MV adaptive beamforming technique is attractive as it is capable of producing high quality images with narrow mainlobe width and low sidelobe level. However, because of its substantially higher computational requirements, realizing MV in real-time has been prohibitively difficult. Recent advancements in commodity GPUs have made very high performance computing possible at very affordable price. Using a commercial off-the-shelf GPU, an MV beam-former achieving real-time performance has been realized. Tradeoffs between computational throughput and image quality have been studied. Careful selection of algorithm parameters, including receive aperture and sub-aperture size, was demonstrated to be imperative for achieving real-time performance without sacrificing image qualities.published_or_final_versionThe 2011 IEEE International Ultrasonics Symposium (IUS), Orlando, FL., 18-21 October 2011. In IEEE International Ultrasonics Symposium Proceedings, 2011, p. 474-47

Medical ultrasound imaging: To GPU or not to GPU?

Medical ultrasound imaging stands out from other modalities in providing real-time diagnostic capability at an affordable price while being physically portable. This article explores the suitability of using GPUs as the primary signal and image processors for future medical ultrasound imaging systems. A case study on synthetic aperture (SA) imaging illustrates the promise of using high-performance GPUs in such systems. © 2011 IEEE.published_or_final_versio

Developmental delays and subcellular stress as downstream effects of sonoporation

Posters: no. 2Control ID: 1672434OBJECTIVES: The biological impact of sonoporation has often been overlooked. Here we seek to obtain insight into the cytotoxic impact of sonoporation by gaining new perspectives on anti-proliferative characteristics that may emerge within sonoporated cells. We particularly focused on investigating the cell-cycle progression kinetics of sonoporated cells and identifying organelles that may be stressed in the recovery process. METHODS: In line with recommendations on exposure hardware design, an immersion-based ultrasound platform has been developed. It delivers 1 MHz ultrasound pulses (100 cycles; 1 kHz PRF; 60 s total duration) with 0.45 MPa peak negative pressure to a cell chamber that housed HL-60 leukemia cells and lipid-shelled microbubbles at a 10:1 cell-tobubble ratio (for 1e6/ml cell density). Calcein was used to facilitate tracking of sonoporated cells with enhanced uptake of exogenous molecules. The developmental trend of sonoporated cells was quantitatively analyzed using BrdU/DNA flow cytometry that monitors the cell population’s DNA synthesis kinetics. This allowed us to measure the temporal progression of DNA synthesis of sonoporated cells. To investigate whether sonoporation would upset subcellular homeostasis, post-exposure cell samples were also assayed for various proteins using Western blot analysis. Analysis focus was placed on the endoplasmic reticulum (ER): an important organelle with multi-faceted role in cellular functioning. The post-exposure observation time spanned between 0-24 h. RESULTS: Despite maintaining viability, sonoporated cells were found to exhibit delays in cell-cycle progression. Specifically, their DNA synthesis time was lengthened substantially (for HL-60 cells: 8.7 h for control vs 13.4 h for the sonoporated group). This indicates that sonoporated cells were under stress: a phenomenon that is supported by our Western blot assays showing upregulation of ER-resident enzymes (PDI, Ero1), ER stress sensors (PERK, IRE1), and ER-triggered pro-apoptotic signals (CHOP, JNK). CONCLUSIONS: Sonoporation, whilst being able to facilitate internalization of exogenous molecules, may inadvertently elicit a cellular stress response. These findings seem to echo recent calls for reconsideration of efficiency issues in sonoporation-mediated drug delivery. Further efforts would be necessary to improve the efficiency of sonoporation-based biomedical applications where cell death is not desirable.postprin

How sonoporation disrupts cellular structural integrity: morphological and cytoskeletal observations

Posters: no. 1Control ID: 1672429OBJECTIVES: In considering sonoporation for drug delivery applications, it is essential to understand how living cells respond to this puncturing force. Here we seek to investigate the effects of sonoporation on cellular structural integrity. We hypothesize that the membrane morphology and cytoskeletal behavior of sonoporated cells under recovery would inherently differ from that of normal viable cells. METHODS: A customized and calibrated exposure platform was developed for this work, and the ZR-75-30 breast carcinoma cells were used as the cell model. The cells were exposed to either single or multiple pulses of 1 MHz ultrasound (pulse length: 30 or 100 cycles; PRF: 1kHz; duration: up to 60s) with 0.45 MPa spatial-averaged peak negative pressure and in the presence of lipid-shelled microbubbles. Confocal microscopy was used to examine insitu the structural integrity of sonoporated cells (identified as ones with exogenous fluorescent marker internalization). For investigations on membrane morphology, FM 4-64 was used as the membrane dye (red), and calcein was used as the sonoporation marker (green); for studies on cytoskeletal behavior, CellLight (green) and propidium iodide (red) were used to respectively label actin filaments and sonoporated cells. Observation started from before exposure to up to 2 h after exposure, and confocal images were acquired at real-time frame rates. Cellular structural features and their temporal kinetics were quantitatively analyzed to assess the consistency of trends amongst a group of cells. RESULTS: Sonoporated cells exhibited membrane shrinkage (decreased by 61% in a cell’s cross-sectional area) and intracellular lipid accumulation (381% increase compared to control) over a 2 h period. The morphological repression of sonoporated cells was also found to correspond with post-sonoporation cytoskeletal processes: actin depolymerization was observed as soon as pores were induced on the membrane. These results show that cellular structural integrity is indeed disrupted over the course of sonoporation. CONCLUSIONS: Our investigation shows that the biophysical impact of sonoporation is by no means limited to the induction of membrane pores: e.g. structural integrity is concomitantly affected in the process. This prompts the need for further fundamental studies to unravel the complex sequence of biological events involved in sonoporation.postprin

Sonoporation-induced endoplasmic reticulum stress: signaling pathway analysis

Session IUS1-K3: Metrology and sonoporation: abstract no. IUS1-K3-6The Conference program & abstracts' website is located at http://www.ewh.ieee.org/conf/uffc/2013/BACKGROUND, MOTIVATION AND OBJECTIVE: Sonoporation can induce a complex range of biological consequences beyond a transient porosity change at the membrane level. In particular, at a subcellular level, the functioning of various organelles may become disrupted. This work represents the first demonstration that the endoplasmic reticulum (ER) (an organelle responsible for protein folding, lipid synthesis, and calcium regulation) may be actively involved in mediating post-sonoporation cellular response. STATEMENT OF CONTRIBUTION/METHODS: We have assayed for various ER-related proteins using Western blot analysis. HL-60 cell suspensions were used …postprin

O uso de jogos e processamento de informação : ganhos e perdas

Dissertação de Mestrado apresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Psicologia Clínica.A área dos videojogos, ainda que se encontre cada vez mais em expansão e com constantes inovações tecnológicas, como podemos verificar através da expansão da realidade virtual (Cheng et al., 2018), é ainda muito pouco explorada, do ponto de vista da investigação científica. Quando falamos do impacto positivo que estes poderão ter na sociedade, esta investigação é ainda mais rara, contrariamente ao que ocorre com o número de estudos e autores que se centram no impacto negativo e nas repercussões negativas. O presente estudo exploratório tem como principal propósito indagar acerca da existência, ou não, de um fator protetor e positivo, e se poderá existir alguma relação entre o grau de dependência nos videojogos, a velocidade de processamento de informação e a qualidade de vida. Deste modo, este poderá vir a ser um importante contributo para a desmistificação no papel dos videojogos no desenvolvimento humano. Participaram 45 sujeitos, com idades compreendidas entre os 19 e os 61 anos, tendo sido utilizados os instrumentos: IGDS9-S, WHOQOL–bref, e tarefas de busca visual em Cenários digitais (Super Lab Pro). Relativamente ao grupo sujeitos com algum grau de dependência, concluiu-se que a velocidade de processamento de informação, não se mostrou positivamente significativa e que apresentaram resultados a nível da qualidade de vida, mais reduzidos.The area of video games, although increasingly expanding and with constant technological innovations, as we can see through the expansion of virtual reality (Cheng, Cheung & Wang, 2018), is still very unexplored from the point of view of scientific research. When we talk about the positive impact they can have on society, this research is even rarer, unlike the number of studies and authors that focus on negative impact and negative repercussions. The present exploratory study aims to determine the existence, or not, of a protective and positive factor, and whether there can be any relationship between the degree of dependence of video games, the speed of information processing and quality of life. This way, this can be an important contribution to the role of video games in human development. This methodology was based on a sample of 45 individuals, aged between 19 and 61 years. and the following instruments were used: IGDS9-S, WHOQOL -bref, and visual search tasks in Digital Scenarios (Super Lab Pro). Regarding the group subjects with some degree of dependence, it was concluded that the speed of information processing was not positively significant and that they presented lower quality of life results

Establishment of a novel human embryonic stem cell-derived trophoblastic spheroid implantation model

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Study of transforming growth factor alpha for the maintenance of human embryonic stem cells

Human embryonic stem cells (hESCs) have great potential for regenerative medicine as they have selfregenerative and pluripotent properties. Feeder cells or their conditioned medium are required for the maintenance of hESC in the undifferentiated state. Feeder cells have been postulated to produce growth factors and extracellular molecules for maintaining hESC in culture. The present study has aimed at identifying these molecules. The gene expression of supportive feeder cells, namely human foreskin fibroblast (hFF-1) and non-supportive human lung fibroblast (WI-38) was analyzed by microarray and 445 genes were found to be differentially expressed. Gene ontology analysis showed that 20.9% and 15.5% of the products of these genes belonged to the extracellular region and regulation of transcription activity, respectively. After validation of selected differentially expressed genes in both human and mouse feeder cells, transforming growth factor a (TGFa) was chosen for functional study. The results demonstrated that knockdown or protein neutralization of TGFa in hFF-1 led to increased expression of early differentiation markers and lower attachment rates of hESC. More importantly, TGFa maintained pluripotent gene expression levels, attachment rates and pluripotency by the in vitro differentiation of H9 under non-supportive conditions. TGFa treatment activated the p44/42MAPK pathway but not the PI3K/Akt pathway. In addition, TGFa treatment increased the expression of pluripotent markers, NANOG and SSEA-3 but had no effects on the proliferation of hESCs. This study of the functional role of TGFa provides insights for the development of clinical grade hESCs for therapeutic applications. © The Author(s) 2012. © Springer-Verlag 2012.published_or_final_versio

Interplay between HIV-1 infection and host microRNAs

Using microRNA array analyses of in vitro HIV-1-infected CD4+ cells, we find that several host microRNAs are significantly up- or downregulated around the time HIV-1 infection peaks in vitro. While microRNA-223 levels were significantly enriched in HIV-1-infected CD4+CD8− PBMCs, microRNA-29a/b, microRNA-155 and microRNA-21 levels were significantly reduced. Based on the potential for microRNA binding sites in a conserved sequence of the Nef-3′-LTR, several host microRNAs potentially could affect HIV-1 gene expression. Among those microRNAs, the microRNA-29 family has seed complementarity in the HIV-1 3′-UTR, but the potential suppressive effect of microRNA-29 on HIV-1 is severely blocked by the secondary structure of the target region. Our data support a possible regulatory circuit at the peak of HIV-1 replication which involves downregulation of microRNA-29, expression of Nef, the apoptosis of host CD4 cells and upregulation of microRNA-223

Dosage-Sensitive Function of RETINOBLASTOMA RELATED and Convergent Epigenetic Control Are Required during the Arabidopsis Life Cycle

The plant life cycle alternates between two distinct multi-cellular generations, the reduced gametophytes and the dominant sporophyte. Little is known about how generation-specific cell fate, differentiation, and development are controlled by the core regulators of the cell cycle. In Arabidopsis, RETINOBLASTOMA RELATED (RBR), an evolutionarily ancient cell cycle regulator, controls cell proliferation, differentiation, and regulation of a subset of Polycomb Repressive Complex 2 (PRC2) genes and METHYLTRANSFERASE 1 (MET1) in the male and female gametophytes, as well as cell fate establishment in the male gametophyte. Here we demonstrate that RBR is also essential for cell fate determination in the female gametophyte, as revealed by loss of cell-specific marker expression in all the gametophytic cells that lack RBR. Maintenance of genome integrity also requires RBR, because diploid plants heterozygous for rbr (rbr/RBR) produce an abnormal portion of triploid offspring, likely due to gametic genome duplication. While the sporophyte of the diploid mutant plants phenocopied wild type due to the haplosufficiency of RBR, genetic analysis of tetraploid plants triplex for rbr (rbr/rbr/rbr/RBR) revealed that RBR has a dosage-dependent pleiotropic effect on sporophytic development, trichome differentiation, and regulation of PRC2 subunit genes CURLY LEAF (CLF) and VERNALIZATION 2 (VRN2), and MET1 in leaves. There were, however, no obvious cell cycle and cell proliferation defects in these plant tissues, suggesting that a single functional RBR copy in tetraploids is capable of maintaining normal cell division but is not sufficient for distinct differentiation and developmental processes. Conversely, in leaves of mutants in sporophytic PRC2 subunits, trichome differentiation was also affected and expression of RBR and MET1 was reduced, providing evidence for a RBR-PRC2-MET1 regulatory feedback loop involved in sporophyte development. Together, dosage-sensitive RBR function and its genetic interaction with PRC2 genes and MET1 must have been recruited during plant evolution to control distinct generation-specific cell fate, differentiation, and development