Publications
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Kumari, Pooja; Tang, Kai & Safarian, Jafar
(2026).
Inclusions in Ultra-low Carbon Ferromanganese Obtained via Aluminothermic Reduction of Different Pre-reduced Mn Ores.
Metallurgical and Materials Transactions B.
ISSN 1073-5615.
57,
p. 2935–2948.
doi:
10.1007/s11663-026-04025-z.
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The inclusions present in manganese ferroalloys produced by aluminothermic reduction of pre-reduced manganese ores were studied by scanning electron microscopy coupled with energy dispersive spectroscopy. Two major categories of alloys were classified and evaluated, one with Si < 1 wt pct mostly containing MnS and complex compounds of manganese oxide, aluminum oxide, silicon oxide, and manganese sulfide. The second type contained Si > 1 wt pct. The second type can be sub-classified based on Fe content as and Fe < 10 wt pct and was found to contain MnO–Al2O3–SiO2–CaO–MgO–MnS similar type of inclusion as the first type except that these inclusions had higher amount of Al2O3 and lower amount of MnO and some amount of CaO and MgO in them. And the other with Fe > 10 wt pct which contained larger-sized (100 μm) MnO–FeO–SiO2 inclusions. This is a new inclusion type not reported elsewhere in ferromanganese alloys. The mechanism of inclusions formation was studied and based on the thermochemistry of the system and morphology of inclusions it was proposed that they are formed upon cooling and solidification via the significant decrease of sulfur and oxygen solubilities in liquid metal. Unlike carbothermic production, aluminothermic reduction generates Al2O3-rich complex inclusions with lower stability and improved removability, offering a cleaner and more efficient pathway for ultra-low carbon ferromanganese synthesis.
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Kumari, Pooja; Thuestad, Lars Harald & Ciosk, Rafal
(2023).
Post-transcriptional repression of CFP-1 expands the regulatory repertoire of LIN-41/TRIM71.
Nucleic Acids Research (NAR).
ISSN 0305-1048.
51(19),
p. 10668–10680.
doi:
10.1093/nar/gkad729.
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Abstract The Caenorhabditis elegans LIN-41/TRIM71 is a well-studied example of a versatile regulator of mRNA fate, which plays different biological functions involving distinct post-transcriptional mechanisms. In the soma, LIN-41 determines the timing of developmental transitions between larval stages. The somatic LIN-41 recognizes specific mRNAs via LREs (LIN-41 Recognition Elements) and elicits either mRNA decay or translational repression. In the germline, LIN-41 controls the oocyte-to-embryo transition (OET), although the relevant targets and regulatory mechanisms are poorly understood. The germline LIN-41 was suggested to regulate mRNAs indirectly by associating with another RNA-binding protein. We show here that LIN-41 can also regulate germline mRNAs via the LREs. Through a computational-experimental analysis, we identified the germline mRNAs potentially controlled via LREs and validated one target, the cfp-1 mRNA, encoding a conserved chromatin modifier. Our analysis suggests that cfp-1 may be a long-sought target whose LIN-41-mediated regulation during OET facilitates the transcriptional reprogramming underlying the switch from germ- to somatic cell identity.
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Sobańska, Daria; Komur, Alicja; Chabowska-Kita, Agnieszka; Gumna, Julita; Kumari, Pooja & Pachulska-Wieczorek, Katarzyna
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(2022).
The silencing of ets-4 mRNA relies on the functional cooperation between REGE-1/Regnase-1 and RLE-1/Roquin-1.
Nucleic Acids Research (NAR).
ISSN 0305-1048.
50(14),
p. 8226–8239.
doi:
10.1093/nar/gkac609.
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Abstract Regnase-1 is an evolutionarily conserved endoribonuclease. It degrades diverse mRNAs important for many biological processes including immune homeostasis, development and cancer. There are two competing models of Regnase-1-mediated mRNA silencing. One model postulates that Regnase-1 works together with another RNA-binding protein, Roquin-1, which recruits Regnase-1 to specific mRNAs. The other model proposes that the two proteins function separately. Studying REGE-1, the Caenorhabditis elegans ortholog of Regnase-1, we have uncovered its functional relationship with RLE-1, the nematode counterpart of Roquin-1. While both proteins are essential for mRNA silencing, REGE-1 and RLE-1 appear to associate with target mRNA independently of each other. Thus, although the functional interdependence between REGE-1/Regnase-1 and RLE-1/Roquin-1 is conserved, the underlying mechanisms may display species-specific variation, providing a rare perspective on the evolution of this important post-transcriptional regulatory mechanism.
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Fassnacht, Christina; Tocchini, Cristina; Kumari, Pooja; Gaidatzis, Dimos; Stadler, Michael B & Ciosk, Rafal
(2018).
The CSR-1 endogenous RNAi pathway ensures accurate transcriptional reprogramming during the oocyte-to-embryo transition in Caenorhabditis elegans.
PLoS Genetics.
ISSN 1553-7390.
doi:
10.1371/journal.pgen.1007252.
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Endogenous RNAi (endoRNAi) is a conserved mechanism for fine-tuning gene expression. In the nematode Caenorhabditis elegans, several endoRNAi pathways are required for the successful development of reproductive cells. The CSR-1 endoRNAi pathway promotes germ cell development, primarily by facilitating the expression of germline genes. In this study, we report a novel function for the CSR-1 pathway in preventing premature activation of embryonic transcription in the developing oocytes, which is accompanied by a general Pol II activation. This CSR-1 function requires its RNase activity, suggesting that, by controlling the levels of maternal mRNAs, CSR-1-dependent endoRNAi contributes to an orderly reprogramming of transcription during the oocyte-to-embryo transition.
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Published
Dec. 6, 2019 11:47 AM
- Last modified
Apr. 8, 2022 11:24 AM