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Daniel Levy - One of the best experts on this subject based on the ideXlab platform.
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the periNuclear er scales Nuclear Size independently of cell Size in early embryos
Developmental Cell, 2020Co-Authors: Richik Nilay Mukherjee, Katherine Nelson, John Oakey, Jeremy Salle, Serge Dmitrieff, Nicolas Minc, Daniel LevyAbstract:Nuclear Size plays pivotal roles in gene expression, embryo development, and disease. A central hypothesis in organisms ranging from yeast to vertebrates is that Nuclear Size scales to cell Size. This implies that nuclei may reach steady-state Sizes set by limiting cytoplasmic pools of Size-regulating components. By monitoring Nuclear dynamics in early sea urchin embryos, we found that nuclei undergo substantial growth in each interphase, reaching a maximal Size prior to mitosis that declined steadily over the course of development. Manipulations of cytoplasmic volume through multiple chemical and physical means ruled out cell Size as a major determinant of Nuclear Size and growth. Rather, our data suggest that the periNuclear endoplasmic reticulum, accumulated through dynein activity, serves as a limiting membrane pool that sets Nuclear surface growth rate. Partitioning of this local pool at each cell division modulates Nuclear growth kinetics and dictates Size scaling throughout early development.
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the nucleoporin elys regulates Nuclear Size by controlling npc number and Nuclear import capacity
EMBO Reports, 2019Co-Authors: Predrag Jevtic, Andria C Schibler, Chase C Wesley, Gianluca Pegoraro, Tom Misteli, Daniel LevyAbstract:Abstract How intracellular organelles acquire their characteristic Sizes is a fundamental question in cell biology. Given stereotypical changes in Nuclear Size in cancer, it is important to understand the mechanisms that control Nuclear Size in human cells. Using a high‐throughput imaging RNAi screen, we identify and mechanistically characterize ELYS, a nucleoporin required for post‐mitotic Nuclear pore complex (NPC) assembly, as a determinant of Nuclear Size in mammalian cells. ELYS knockdown results in small nuclei, reduced Nuclear lamin B2 localization, lower NPC density, and decreased Nuclear import. Increasing Nuclear import by importin α overexpression rescues Nuclear Size and lamin B2 import, while inhibiting importin α/β‐mediated Nuclear import decreases Nuclear Size. Conversely, ELYS overexpression increases Nuclear Size, enriches Nuclear lamin B2 at the Nuclear periphery, and elevates NPC density and Nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases Nuclear Size. Thus, we identify ELYS as a novel positive effector of mammalian Nuclear Size and propose that Nuclear Size is sensitive to NPC density and Nuclear import capacity.
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cytoplasmic volume and limiting nucleoplasmin scale Nuclear Size during xenopus laevis development
bioRxiv, 2019Co-Authors: Pan Chen, Miroslav Tomschik, Katherine Nelson, John Oakey, Jesse C Gatlin, Daniel LevyAbstract:SUMMARY How Nuclear Size is regulated relative to cell Size is a fundamental cell biological question. Reductions in both cell and Nuclear Sizes during Xenopus laevis embryogenesis provide a robust scaling system to study mechanisms of Nuclear Size regulation. To test if the volume of embryonic cytoplasm is limiting for Nuclear growth, we encapsulated gastrula stage embryonic cytoplasm and nuclei in droplets of defined volume using microfluidics. Nuclei grew and reached new steady-state Sizes as a function of cytoplasmic volume, supporting a limiting component mechanism of Nuclear Size control. Through biochemical fractionation, we identified the histone chaperone nucleoplasmin (Npm2) as a putative Nuclear Size-scaling factor. Cellular amounts of Npm2 decrease over development, and Nuclear Size was sensitive to Npm2 levels both in vitro and in vivo, affecting Nuclear histone levels and chromatin organization. Thus, reductions in cell volume with concomitant decreases in Npm2 amounts represent a developmental mechanism of Nuclear Size-scaling that may also be relevant to cancers with increased Nuclear Size.
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The nucleoporin ELYS regulates Nuclear Size by controlling NPC number and Nuclear import capacity
bioRxiv, 2019Co-Authors: Predrag Jevtic, Andria C Schibler, Gianluca Pegoraro, Tom Misteli, Daniel LevyAbstract:How intracellular organelles acquire their characteristic Sizes is a fundamental cell biological question. Given the stereotypical changes in Nuclear Size in cancer, it is particularly important to understand the mechanisms that control Nuclear Size in human cells. Here we use a high-throughput imaging RNAi screen to identify and mechanistically characterize ELYS, a nucleoporin required for postmitotic Nuclear pore complex (NPC) assembly, as a determinant of Nuclear Size in mammalian cells. We show that ELYS knockdown results in small nuclei, the accumulation of cytoplasmic lamin aggregates, reduced Nuclear lamin B2 localization, lower NPC density, and decreased Nuclear import. Increasing Nuclear import by importin α overexpression rescues Nuclear Size and lamin B2 import, while inhibiting importin α/β Nuclear import decreases Nuclear Size. Conversely, ELYS overexpression leads to increased Nuclear Size, enrichment of Nuclear lamin B2 staining at the Nuclear periphery, and elevated NPC density and Nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases Nuclear Size. In summary, we identify ELYS and NPC density as novel positive effectors of mammalian Nuclear Size and propose that Nuclear Size is controlled by Nuclear import capacity.
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both Nuclear Size and dna amount contribute to midblastula transition timing in xenopus laevis
Scientific Reports, 2017Co-Authors: Predrag Jevtic, Daniel LevyAbstract:During early Xenopus laevis embryogenesis both Nuclear and cell volumes decrease with the Nuclear-to-cytoplasmic (N/C) volume ratio reaching a maximum at the midblastula transition (MBT). At the MBT, embryonic transcription is upregulated and cell cycles lengthen. Early studies demonstrated a role for the DNA-to-cytoplasmic ratio in the control of MBT timing. By altering Nuclear Size, we previously showed that the N/C volume ratio also contributes to proper MBT timing. Here we examine the relative contributions of Nuclear Size and DNA amount to MBT timing by simultaneously altering Nuclear Size and ploidy in X. laevis embryos. Compared to diploid embryos, haploids exhibited a delay in both zygotic gene expression and cell cycle lengthening, while diploid embryos with increased N/C volume ratios showed early expression of zygotic genes and premature lengthening of cell cycles. Interestingly, haploids with increased N/C volume ratios exhibited an intermediate effect on the timing of zygotic gene expression and cell cycle lengthening. Decreasing Nuclear Size in post-MBT haploid embryos caused a further delay in cell cycle lengthening and the expression of some zygotic genes. Our data suggest that both the N/C volume ratio and DNA amount contribute to the regulation of MBT timing with neither parameter being dominant.
Predrag Jevtic - One of the best experts on this subject based on the ideXlab platform.
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the nucleoporin elys regulates Nuclear Size by controlling npc number and Nuclear import capacity
EMBO Reports, 2019Co-Authors: Predrag Jevtic, Andria C Schibler, Chase C Wesley, Gianluca Pegoraro, Tom Misteli, Daniel LevyAbstract:Abstract How intracellular organelles acquire their characteristic Sizes is a fundamental question in cell biology. Given stereotypical changes in Nuclear Size in cancer, it is important to understand the mechanisms that control Nuclear Size in human cells. Using a high‐throughput imaging RNAi screen, we identify and mechanistically characterize ELYS, a nucleoporin required for post‐mitotic Nuclear pore complex (NPC) assembly, as a determinant of Nuclear Size in mammalian cells. ELYS knockdown results in small nuclei, reduced Nuclear lamin B2 localization, lower NPC density, and decreased Nuclear import. Increasing Nuclear import by importin α overexpression rescues Nuclear Size and lamin B2 import, while inhibiting importin α/β‐mediated Nuclear import decreases Nuclear Size. Conversely, ELYS overexpression increases Nuclear Size, enriches Nuclear lamin B2 at the Nuclear periphery, and elevates NPC density and Nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases Nuclear Size. Thus, we identify ELYS as a novel positive effector of mammalian Nuclear Size and propose that Nuclear Size is sensitive to NPC density and Nuclear import capacity.
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The nucleoporin ELYS regulates Nuclear Size by controlling NPC number and Nuclear import capacity
bioRxiv, 2019Co-Authors: Predrag Jevtic, Andria C Schibler, Gianluca Pegoraro, Tom Misteli, Daniel LevyAbstract:How intracellular organelles acquire their characteristic Sizes is a fundamental cell biological question. Given the stereotypical changes in Nuclear Size in cancer, it is particularly important to understand the mechanisms that control Nuclear Size in human cells. Here we use a high-throughput imaging RNAi screen to identify and mechanistically characterize ELYS, a nucleoporin required for postmitotic Nuclear pore complex (NPC) assembly, as a determinant of Nuclear Size in mammalian cells. We show that ELYS knockdown results in small nuclei, the accumulation of cytoplasmic lamin aggregates, reduced Nuclear lamin B2 localization, lower NPC density, and decreased Nuclear import. Increasing Nuclear import by importin α overexpression rescues Nuclear Size and lamin B2 import, while inhibiting importin α/β Nuclear import decreases Nuclear Size. Conversely, ELYS overexpression leads to increased Nuclear Size, enrichment of Nuclear lamin B2 staining at the Nuclear periphery, and elevated NPC density and Nuclear import. Consistent with these observations, knockdown or inhibition of exportin 1 increases Nuclear Size. In summary, we identify ELYS and NPC density as novel positive effectors of mammalian Nuclear Size and propose that Nuclear Size is controlled by Nuclear import capacity.
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both Nuclear Size and dna amount contribute to midblastula transition timing in xenopus laevis
Scientific Reports, 2017Co-Authors: Predrag Jevtic, Daniel LevyAbstract:During early Xenopus laevis embryogenesis both Nuclear and cell volumes decrease with the Nuclear-to-cytoplasmic (N/C) volume ratio reaching a maximum at the midblastula transition (MBT). At the MBT, embryonic transcription is upregulated and cell cycles lengthen. Early studies demonstrated a role for the DNA-to-cytoplasmic ratio in the control of MBT timing. By altering Nuclear Size, we previously showed that the N/C volume ratio also contributes to proper MBT timing. Here we examine the relative contributions of Nuclear Size and DNA amount to MBT timing by simultaneously altering Nuclear Size and ploidy in X. laevis embryos. Compared to diploid embryos, haploids exhibited a delay in both zygotic gene expression and cell cycle lengthening, while diploid embryos with increased N/C volume ratios showed early expression of zygotic genes and premature lengthening of cell cycles. Interestingly, haploids with increased N/C volume ratios exhibited an intermediate effect on the timing of zygotic gene expression and cell cycle lengthening. Decreasing Nuclear Size in post-MBT haploid embryos caused a further delay in cell cycle lengthening and the expression of some zygotic genes. Our data suggest that both the N/C volume ratio and DNA amount contribute to the regulation of MBT timing with neither parameter being dominant.
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Nuclear Size is sensitive to ntf2 protein levels in a manner dependent on ran binding
Journal of Cell Science, 2016Co-Authors: Lidija Vukovic, Predrag Jevtic, Zhaojie Zhang, Bradley A Stohr, Daniel LevyAbstract:Altered Nuclear Size is associated with many cancers, and determining whether cancer-associated changes in Nuclear Size contribute to carcinogenesis necessitates an understanding of mechanisms of Nuclear Size regulation. Although Nuclear import rates generally positively correlate with Nuclear Size, NTF2 levels negatively affect Nuclear Size, despite the role of NTF2 (also known as NUTF2) in Nuclear recycling of the import factor Ran. We show that binding of Ran to NTF2 is required for NTF2 to inhibit Nuclear expansion and import of large cargo molecules in Xenopus laevis egg and embryo extracts, consistent with our observation that NTF2 reduces the diameter of the Nuclear pore complex (NPC) in a Ran-binding-dependent manner. Furthermore, we demonstrate that ectopic NTF2 expression in Xenopus embryos and mammalian tissue culture cells alters Nuclear Size. Finally, we show that increases in Nuclear Size during melanoma progression correlate with reduced NTF2 expression, and increasing NTF2 levels in melanoma cells is sufficient to reduce Nuclear Size. These results show a conserved capacity for NTF2 to impact on Nuclear Size, and we propose that NTF2 might be a new cancer biomarker.
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Nuclear Size scaling during xenopus early development contributes to midblastula transition timing
Current Biology, 2015Co-Authors: Predrag Jevtic, Daniel LevyAbstract:Summary Early Xenopus laevis embryogenesis is a robust system for investigating mechanisms of developmental timing. After a series of rapid cell divisions with concomitant reductions in cell Size, the first major developmental transition is the midblastula transition (MBT), when zygotic transcription begins and cell cycles elongate [1–3]. Whereas the maintenance of a constant Nuclear-to-cytoplasmic (N/C) volume ratio is a conserved cellular property [4–7], it has long been recognized that the N/C volume ratio changes dramatically during early Xenopus development [8]. We investigated how changes in Nuclear Size and the N/C volume ratio during early development contribute to the regulation of MBT timing. Whereas previous studies suggested a role for the N/C volume ratio in MBT timing [1, 9–13], none directly tested the effects of altering Nuclear Size. In this study, we first quantify blastomere and Nuclear Sizes in X. laevis embryos, demonstrating that the N/C volume ratio increases prior to the MBT. We then manipulate Nuclear volume in embryos by microinjecting different Nuclear scaling factors, including import proteins, lamins, and reticulons. Using this approach, we show that increasing the N/C volume ratio in pre-MBT embryos leads to premature activation of zygotic gene transcription and early onset of longer cell cycles. Conversely, decreasing the N/C volume ratio delays zygotic transcription and leads to additional rapid cell divisions. Whereas the DNA-to-cytoplasmic ratio has been implicated in MBT timing [1, 9–18], our data show that Nuclear Size also contributes to the regulation of MBT timing, demonstrating the functional significance of Nuclear Size during development.
Jiefu Chen - One of the best experts on this subject based on the ideXlab platform.
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abstract 4331 Nuclear Size of circulating tumor cells is associated with prognosis in metastatic castration resistant prostate cancer
Endocrinology, 2020Co-Authors: Jasmine J Wang, Jiefu Chen, Paichi Teng, Yu Jen Jan, Galen Cookwiens, Nu Yao, Gina Chiayi Chu, Pinjung Chen, Yingying Yang, Yee Hui YeoAbstract:Background: Current risk stratification models in prostate cancer (PC) have been based on clinical and pathological variables. Beyond serum prostate-specific antigen (PSA) concentration measurements, there remain few new biomarkers to help identify patients at risk for poor clinical outcomes. Morphological analyses using Gleason scoring along with cell Nuclear Size and shape remains to be a fundamental pathological practice of PC that have been utilized to identify aggressive diseases and to associate with aggressive metastasis. In particular, changes in Nuclear shape and composition have been associated with outcome in early stage disease. Circulating tumor cells (CTCs) have arisen as contemporary noninvasive prognostic biomarkers for PC. Previously, a subgroup of PC CTCs, with prominently small nuclei ( Methods: In this study, 76 patients with mCRPC were recruited for overall survival (OS) analysis. Of the 76 patients, 50 had available pre-treatment blood specimens prior to the initiation of androgen receptor signaling inhibitor (ARSI, e.g. abiraterone and enzalutamide) or taxane or tyrosine kinase inhibitor therapy. Using the NanoVelcro CTC Enumeration Assay, CTCs were captured and subjected to immunofluorescence staining. CTCs were identified as DAPI+/CK+/CD45- with a round or oval nucleus. Additionally, CTC Nuclear Size was measured and defined as the square root of the product of the long axis and the short axis. Kaplan-Meier analysis and Cox proportional hazards model were conducted. Results: Patients with vsnCTC (i.e., vsnCTC+) had a significantly shortened OS compared with patients without vsnCTC (i.e., vsnCTC-). The median OS was 34 (vsnCTC+, n=49) vs. 149 (vsnCTC-, n=27) weeks (log-rank HR=2.6 with 95% CI 1.5 to 4.5, p=0.0006). Progression free survival (PFS) analysis was performed for the 50 patients with pre-treatment blood samples. The median PFS was 12 (vsnCTC+, n=32) vs. 26 (vsnCTC-, n=18) weeks (log-rank HR=2.2 with 95% CI 1.3 to 4.0, p=0.0038). We also found that the hazard ratio of overall survival increased significantly as the CTC Nuclear Size decreased using the p-spline plot. Conclusions: Our study showed that Nuclear Size reduction has importance in CTCs in a fashion similar to its utility in tissue. This study points toward the importance of the vsnCTC in patients with mCRPC, as vsnCTC+ patients represented a group at risk for faster clinical progression who are at the highest risk for morality. We posit that the vsnCTC represents a new hallmark of an aggressive subtype of mCRPC. This has potential importance in optimizing therapeutic choices. Citation Format: JASMINE J. WANG, Pai-Chi Teng, Yu Jen Jan, Jie-Fu Chen, Galen Cook-Wiens, Nu Yao, Gina C. Chu, Pin-Jung Chen, Yingying Yang, Yee Hui Yeo, Yi-Te Lee, Leland W. Chung, Sungyong You, Yazhen Zhu, Michael R. Freeman, Andre Rogatko, Ju Dong Yang, Hsian-Rong Tseng, Edwin M. Posadas. Nuclear Size of circulating tumor cells is associated with prognosis in metastatic, castration-resistant prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4331.
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circulating tumor cells with small Nuclear Size a novel biomarker for survival and clinical outcomes in advanced prostate cancer
Journal of Clinical Oncology, 2020Co-Authors: Jasmine J Wang, Jiefu Chen, Paichi Teng, Yu Jen Jan, Galen Cookwiens, Nu Yao, Gina Chiayi Chu, Pinjung Chen, Yite Lee, Jiaoti HuangAbstract:e17512Background: Very-small-Nuclear circulating tumor cells (vsnCTCs) as a subset of CTCs with Nuclear Size < 8.5 μm associated with visceral metastases (VM) in advanced metastatic, castration-res...
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subclassification of prostate cancer circulating tumor cells by Nuclear Size reveals very small Nuclear circulating tumor cells in patients with visceral metastases
Cancer, 2015Co-Authors: Jiefu Chen, Jake Lichterman, Yang Zhang, M A Garcia, Shangfu Chen, Anjou Liang, Elisabeth Hodara, Haiyen E Zhau, Shuang Hou, Rafi S AhmedAbstract:BACKGROUND Although enumeration of circulating tumor cells (CTCs) has shown some clinical value, the pool of CTCs contains a mixture of cells that contains additional information that can be extracted. The authors subclassified CTCs by shape features focusing on Nuclear Size and related this with clinical information. METHODS A total of 148 blood samples were obtained from 57 patients with prostate cancer across the spectrum of metastatic states: no metastasis, nonvisceral metastasis, and visceral metastasis. CTCs captured and enumerated on NanoVelcro Chips (CytoLumina, Los Angeles, Calif) were subjected to pathologic review including Nuclear Size. The distribution of Nuclear Size was analyzed using a Gaussian mixture model. Correlations were made between CTC subpopulations and metastatic status. RESULTS Statistical modeling of Nuclear Size distribution revealed 3 distinct subpopulations: large Nuclear CTCs, small Nuclear CTCs, and very small Nuclear CTCs (vsnCTCs). Small Nuclear CTCs and vsnCTC identified those patients with metastatic disease. However, vsnCTC counts alone were found to be elevated in patients with visceral metastases when compared with those without (0.36 ± 0.69 vs 1.95 ± 3.77 cells/mL blood; P<.001). Serial enumeration studies suggested the emergence of vsnCTCs occurred before the detection of visceral metastases. CONCLUSIONS There are morphologic subsets of CTCs that can be identified by fundamental pathologic approaches, such as Nuclear Size measurement. The results of this observational study strongly suggest that CTCs contain relevant information regarding disease status. In particular, the detection of vsnCTCs was found to be correlated with the presence of visceral metastases and should be formally explored as a putative blood-borne biomarker to identify patients at risk of developing this clinical evolution of prostate cancer. Cancer 2015;121:3240–3251. © 2015 American Cancer Society.
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abstract 3473 sub classification of prostate cancer circulating tumor cells ctcs by Nuclear Size reveals very small Nuclear ctcs in patients with visceral metastases
Cancer Research, 2015Co-Authors: Jiefu Chen, Jake Lichterman, Yang Zhang, M A Garcia, Shangfu Chen, Anjou Liang, Haiyen E Zhau, Shuang Hou, Rafi S Ahmed, Daniel LuthringerAbstract:Background Circulating tumor cells (CTCs) are an emerging biomarker in prostate cancer (PC). Most efforts have focused on enumeration, we and others have identified subsets within this pool of cells which may be clinically informative. Using the highly sensitive NanoVelcro technology for CTC isolation and fluorescence microscopy, our group sub-classified CTCs by Nuclear Size and focused on the correlation with sites of metastatic disease in advanced PC patients. Methods Blood samples were obtained from PC patients across the spectrum of metastatic states, i.e. no metastasis, non-visceral (osseous/lymph node) metastasis, and visceral metastasis. The patients were divided into training and validation cohorts. CTCs were captured from the blood and enumerated on NanoVelcro Chips. These were then subjected to pathologic review for cellular morphology and Nuclear Size. The distribution of Nuclear Sizes was analyzed using a Gaussian Mixture Model to sub-classify the CTCs. Correlations were made between CTC subpopulations and metastatic status. Individual CTCs were isolated by laser-capture microdissection for subsequent characterization focusing on cellular markers and transcriptomic signatures in comparison between vsnCTC and other CTC subpopulations. Results Statistical analysis and modeling of Nuclear Size distribution revealed 3 distinct subpopulations in the training cohort: large-Nuclear CTCs (lnCTC), small-Nuclear CTCs (snCTC), and very-small-Nuclear CTCs (vsnCTCs). While the lnCTC subpopulation alone failed to distinguish metastatic disease from non-metastatic disease, snCTC + vsnCTC counts could make that distinction. Furthermore, vsnCTC counts were elevated in PC patients with visceral metastases when compared to those without visceral metastases (0.5 ± 0.5 versus 3.1 ± 5.2 cells/mL of blood, p = 0.005). This difference remained statistically significant in the validation cohort (0.6 ± 1.0 versus 3.5 ± 4.0 cells/mL of blood, p = 0.007). Serial enumerations for individual patients showed the emergence of vsnCTCs prior to detection of newly developed visceral lesions. The recurrence of vsnCTC in patients under treatment is also associated with radiographic progression of existing visceral lesions through therapy. Molecular characterization of vsnCTCs reveals differential expression of genes related to neuroendocrine, stem cell, and androgen biology. Conclusions Subsets of CTCs contain information on PC disease status when analyzed with pathologic approaches, such as Nuclear Size measurement. In particular, the detection of vsnCTCs correlated with the presence of visceral metastatic lesions and should be explored as a potential biomarker to identify patients at risk for developing this more aggressive form of PC. Citation Format: Jie-Fu Chen, Hao Ho, Jake Lichterman, Yi-Tsung Lu, Yang Zhang, Mitch A. Garcia, Shang-Fu Chen, An-Jou Liang, Haiyen E. Zhau, Shuang Hou, Rafi S. Ahmed, Daniel J. Luthringer, Jiaoti Huang, Ker-Chau Li, Leland WK Chung, Zunfu Ke, Hsian-Rong Tseng, Edwin M. Posadas. Sub-classification of prostate cancer circulating tumor cells (CTCs) by Nuclear Size reveals very-small Nuclear CTCs in patients with visceral metastases. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3473. doi:10.1158/1538-7445.AM2015-3473
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subclassification of prostate cancer circulating tumor cells ctcs by Nuclear Size reveals very small Nuclear ctcs in patients with visceral metastases
Journal of Clinical Oncology, 2015Co-Authors: Jiefu Chen, Jake Lichterman, Leland W K Chung, Hsianrong Tseng, Edwin M PosadasAbstract:11027 Background: In prostate cancer (PCa), morphologic classification remains a standard clinical practice in pathology. It has been shown that Nuclear Size and shape in tumor sections correlate w...
W G Jiang - One of the best experts on this subject based on the ideXlab platform.
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charge radii of exotic potassium isotopes challenge Nuclear theory and the magic character of n 32
Nature Physics, 2021Co-Authors: A Koszorus, X F Yang, W G Jiang, S J Novario, S W BaiAbstract:Nuclear charge radii are sensitive probes of different aspects of the nucleon-nucleon interaction and the bulk properties of Nuclear matter; thus, they provide a stringent test and challenge for Nuclear theory. The calcium region has been of particular interest, as experimental evidence has suggested a new magic number at $N = 32$ [1-3], while the unexpectedly large increases in the charge radii [4,5] open new questions about the evolution of Nuclear Size in neutron-rich systems. By combining the collinear resonance ionization spectroscopy method with $\beta$-decay detection, we were able to extend the charge radii measurement of potassium ($Z =19$) isotopes up to the exotic $^{52}$K ($t_{1/2}$ = 110 ms), produced in minute quantities. Our work provides the first charge radii measurement beyond $N = 32$ in the region, revealing no signature of the magic character at this neutron number. The results are interpreted with two state-of-the-art Nuclear theories. For the first time, a long sequence of isotopes could be calculated with coupled-cluster calculations based on newly developed Nuclear interactions. The strong increase in the charge radii beyond $N = 28$ is not well captured by these calculations, but is well reproduced by Fayans Nuclear density functional theory, which, however, overestimates the odd-even staggering effect. These findings highlight our limited understanding on the Nuclear Size of neutron-rich systems, and expose pressing problems that are present in some of the best current models of Nuclear theory.
A Koszorus - One of the best experts on this subject based on the ideXlab platform.
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charge radii of exotic potassium isotopes challenge Nuclear theory and the magic character of n 32
Nature Physics, 2021Co-Authors: A Koszorus, X F Yang, W G Jiang, S J Novario, S W BaiAbstract:Nuclear charge radii are sensitive probes of different aspects of the nucleon-nucleon interaction and the bulk properties of Nuclear matter; thus, they provide a stringent test and challenge for Nuclear theory. The calcium region has been of particular interest, as experimental evidence has suggested a new magic number at $N = 32$ [1-3], while the unexpectedly large increases in the charge radii [4,5] open new questions about the evolution of Nuclear Size in neutron-rich systems. By combining the collinear resonance ionization spectroscopy method with $\beta$-decay detection, we were able to extend the charge radii measurement of potassium ($Z =19$) isotopes up to the exotic $^{52}$K ($t_{1/2}$ = 110 ms), produced in minute quantities. Our work provides the first charge radii measurement beyond $N = 32$ in the region, revealing no signature of the magic character at this neutron number. The results are interpreted with two state-of-the-art Nuclear theories. For the first time, a long sequence of isotopes could be calculated with coupled-cluster calculations based on newly developed Nuclear interactions. The strong increase in the charge radii beyond $N = 28$ is not well captured by these calculations, but is well reproduced by Fayans Nuclear density functional theory, which, however, overestimates the odd-even staggering effect. These findings highlight our limited understanding on the Nuclear Size of neutron-rich systems, and expose pressing problems that are present in some of the best current models of Nuclear theory.
