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1.
Nature ; 601(7894): 514-515, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-35082426
2.
Plant Cell Physiol ; 61(1): 29-40, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31410484

RESUMO

Angiosperms exhibit double fertilization, a process in which one of the sperm cells released from the pollen tube fertilizes the egg, while the other sperm cell fertilizes the central cell, giving rise to the embryo and endosperm, respectively. We have previously reported two polar nuclear fusion-defective double knockout mutants of Arabidopsis thaliana immunoglobulin binding protein (BiP), a molecular chaperone of the heat shock protein 70 (Hsp70) localized in the endoplasmic reticulum (ER), (bip1 bip2) and its partner ER-resident J-proteins, ERdj3A and P58IPK (erdj3a p58ipk). These mutants are defective in the fusion of outer nuclear membrane and exhibit characteristic seed developmental defects after fertilization with wild-type pollen, which are accompanied by aberrant endosperm nuclear proliferation. In this study, we used time-lapse live-cell imaging analysis to determine the cause of aberrant endosperm nuclear division in these mutant seeds. We found that the central cell of bip1 bip2 or erdj3a p58ipk double mutant female gametophytes was also defective in sperm nuclear fusion at fertilization. Sperm nuclear fusion was achieved after the onset of the first endosperm nuclear division. However, division of the condensed sperm nucleus resulted in aberrant endosperm nuclear divisions and delayed expression of paternally derived genes. By contrast, the other double knockout mutant, erdj3b p58ipk, which is defective in the fusion of inner membrane of polar nuclei but does not show aberrant endosperm nuclear proliferation, was not defective in sperm nuclear fusion at fertilization. We thus propose that premitotic sperm nuclear fusion in the central cell is critical for normal endosperm nuclear proliferation.


Assuntos
Núcleo Celular/metabolismo , Proliferação de Células/fisiologia , Endosperma/fisiologia , Fertilização/fisiologia , Fusão Nuclear , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Retículo Endoplasmático/metabolismo , Endosperma/citologia , Endosperma/genética , Fertilização/genética , Técnicas de Inativação de Genes , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP70 , Chaperonas Moleculares/genética , Membrana Nuclear , Óvulo Vegetal/genética , Pólen/metabolismo , Tubo Polínico/metabolismo
3.
Nature ; 565(7741): 577-578, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30700874
6.
Biofizika ; 61(2): 405-14, 2016.
Artigo em Russo | MEDLINE | ID: mdl-27192844

RESUMO

It is known that in quantum mechanics the act of observing the experiment can affect the experimental findings in some cases. In particular, it happens under the so-called Zeno effect. In this work it is shown that in contrast to the "standard" Zeno-effect where the act of observing a process reduces the probability of its reality, an inverse situation when a particle transmits through a potential barrier (a so-called barrier anti-Zeno effect) can be observed, the observation of the particle essentially increases the probability of its transmission through the barrier. The possibility of using the barrier anti-Zeno effect is discussed to explain paradoxical results of experiments on "cold nuclear fusion" observed in various systems including biological ones. (According to the observers who performed the observations, the energy generation, which could not be explained by any chemical processes, as well as the change in the isotope and even element composition of the studied object may occur in these systems.


Assuntos
Fenômenos Químicos , Modelos Teóricos , Fusão Nuclear , Probabilidade , Teoria Quântica , Temperatura
7.
Roum Arch Microbiol Immunol ; 75(1-2): 44-51, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-29616533

RESUMO

Polyploidization is one of the most dramatic changes occurring within cell genome owing to various reasons including under many viral infections. We examined the impact of herpes simplex virus-1 (HSV-1) on SK-N-MC human neuroblastoma cell line. The infected cells were followed from 6 hours up to 96 hours post infection (hpi). A large number of polyploid cells with giant nuclei was observed under the influence of HSV-1 at 24 hpi with the DNA content of 32c to 64c or more, in comparison with control SK-N-MC cells that were characterized by relatively moderate values of ploidy, i.e. 8с to 16с (where 1c is the haploid amount of nuclear DNA found in normal diploid populations in G0/G1). After 48-96 hpi, the population of polyploid cells with giant nuclei decreased to the benchmark level. The SK-NMC cells infected with HSV-1 for 24 hours were stained with gallocyanine and monitored for cytological features. The infected cells underwent virus induced cellcell and nuclei fusion with the formation of dense nuclei syncytium. The metabolic activity of HSV-1 infected cells was higher in both nuclei and nucleoli when compared to control cells.


Assuntos
Herpesvirus Humano 1/fisiologia , Neuroblastoma/patologia , Poliploidia , Fusão Celular , Linhagem Celular Tumoral , DNA/análise , Células Gigantes/ultraestrutura , Células Gigantes/virologia , Humanos , Fusão Nuclear
8.
Exp Cell Res ; 328(1): 156-163, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25016285

RESUMO

Most previous studies have linked cancer-macrophage fusion with tumor progression and metastasis. However, the characteristics of hybrid cells derived from oral cancer and endothelial cells and their involvement in cancer remained unknown. Double-immunofluorescent staining and fluorescent in situ hybridization (FISH) were performed to confirm spontaneous cell fusion between eGFP-labeled human umbilical vein endothelial cells (HUVECs) and RFP-labeled SCC9, and to detect the expression of vementin and cytokeratin 18 in the hybrids. The property of chemo-resistance of such hybrids was examined by TUNEL assay. The hybrid cells in xenografted tumor were identified by FISH and GFP/RFP dual-immunofluoresence staining. We showed that SCC9 cells spontaneously fused with cocultured endothelial cells, and the resultant hybrid cells maintained the division and proliferation activity after re-plating and thawing. Such hybrids expressed markers of both parental cells and became more resistant to chemotherapeutic drug cisplatin as compared to the parental SCC9 cells. Our in vivo data indicated that the hybrid cells contributed to tumor composition by using of immunostaining and FISH analysis, even though the hybrid cells and SCC9 cells were mixed with 1:10,000, according to the FACS data. Our study suggested that the fusion events between oral cancer and endothelial cells undergo nuclear fusion and acquire a new property of drug resistance and consequently enhanced survival potential. These experimental findings provide further supportive evidence for the theory that cell fusion is involved in cancer progression.


Assuntos
Carcinoma de Células Escamosas/patologia , Fusão Celular , Células Endoteliais da Veia Umbilical Humana/citologia , Células Híbridas/patologia , Neoplasias Bucais/patologia , Fusão Nuclear , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/genética , Comunicação Celular , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos , Feminino , Imunofluorescência , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Células Híbridas/efeitos dos fármacos , Células Híbridas/metabolismo , Hibridização in Situ Fluorescente , Queratina-18/metabolismo , Camundongos , Camundongos Nus , Neoplasias Bucais/tratamento farmacológico , Neoplasias Bucais/genética , Células Tumorais Cultivadas , Vimentina/metabolismo
9.
Molecules ; 19(10): 17052-65, 2014 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-25342556

RESUMO

Deuterated polyethylene targets have been irradiated by means of a 1016 W/cm2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 108 fusions per laser shot was calculated.


Assuntos
Deutério/química , Deutério/efeitos da radiação , Lasers , Fusão Nuclear , Gases em Plasma/química , Polietileno/química , Polietileno/efeitos da radiação , Nêutrons , Prótons
10.
Naturwissenschaften ; 100(9): 899-900, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23949247

RESUMO

This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.


Assuntos
Deutério , Fusão Nuclear , Trítio
11.
Proc Natl Acad Sci U S A ; 107(4): 1684-9, 2010 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-20080634

RESUMO

Nuclear fusion is an essential process in the sexual reproduction of animals and plants. In flowering plants, nuclear fusion occurs three times: once during female gametogenesis, when the two polar nuclei fuse to produce the diploid central cell nucleus, and twice during double fertilization. The yeast Ig binding protein (BiP) is a molecular chaperone Hsp70 in the endoplasmic reticulum that regulates nuclear membrane fusion during mating. Here we report that in Arabidopsis thaliana, BiP is involved in the fusion of polar nuclei during female gametophyte development. BiP-deficient mature female gametophytes contain two unfused polar nuclei, in spite of their close contact. This indicates a surprising conservation of BiP function in nuclear fusion between plants and yeasts. We also found that endosperm nuclear division becomes aberrant after fertilization of the BiP-deficient female gametophytes with wild-type pollen. This is experimental evidence for the importance of fusion of the polar nuclei in the proliferation of endosperm nuclei.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Transporte/metabolismo , Núcleo Celular/metabolismo , Endosperma/citologia , Endosperma/metabolismo , Fusão Nuclear , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Proteínas de Transporte/genética , Proliferação de Células , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Microscopia Eletrônica de Transmissão
12.
Sci Rep ; 12(1): 8276, 2022 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-35585120

RESUMO

We open an avenue for discussing how we can pave the way for compliance with existing regulations is a far-reaching factor for settling nuclear fusion technology. Based on a model of the Korean Fusion Demonstration Reactor (K-DEMO) with a target fusion power of 2.2 GW, we assess the intrinsic safety determinants of internal energy sources, the expected radioactive waste, and the tritium management. Regarding these safety factors, we scrutinize the compatibility of the current legislative environment in Korea with K-DEMO and envisage foreseeable obstacles, such as licensing of the nuclear facilities and acceptability of the radioactive waste. Based on precedent licenses for the Korean Superconducting Tokamak Advanced Research (KSTAR) and lessons learned from the International Thermonuclear Experimental Reactor (ITER), we examine hazardous factors that would threaten regulatory compliance of K-DEMO. This approach can help shape a fusion-compatible framework for consolidating the necessary technical provisions and regulatory baselines reflecting social acceptance with a sense of safety. Fusion-compatible aspects in the regulatory environment are discussed, from fusion philosophy to subordinate administrative and technical guidelines, facility classification, and detailed methods guaranteeing integrity and safety. This paper will contribute to the timely settlement of fusion demonstration facilities and subsequent commercial plants.


Assuntos
Resíduos Radioativos , Fontes Geradoras de Energia , Fusão Nuclear , Reatores Nucleares , Trítio
13.
J Environ Radioact ; 255: 107049, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36274505

RESUMO

Technetium-99m, the decay product of molybdenum-99, is the most used medical isotope in diagnostic imaging. The future disruptions of molybdenum-99 supply, due to the final shut down of some old producing reactors, has led some current global supplies to plan the expansion of their production capacity. While other countries are developing own production facilities to supply their domestic demand. The global increase of molybdenum-99 production in the coming years could increase by about five times the current demand, with about the 50 percent of additional production in North America. Xenon radionuclides are an inevitable by-product of the nuclear plants production, and their periodically release into the atmosphere, contribute to the background that is also revealed by the IMS stations of the CBTO treaty. In this framework, the development of new technologies, posing no risk in relation to nuclear proliferation and do not result in emissions of radioxenon, could mitigate the issues related to the forecast increase of molybdenum-99 production worldwide. In Italy, an alternative 99Mo production project, the project ENEA Sorgentina, based on the irradiation of molybdenum by neutrons produced by a deuterium-tritium nuclear fusion process, is under development. This facility will not release radioxenon into the atmosphere, so it will not affect the background value in the atmosphere in Southern Europe.


Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Molibdênio , Radioisótopos de Xenônio/análise , Fusão Nuclear , Monitoramento de Radiação/métodos , Poluentes Radioativos do Ar/análise , Radioisótopos
15.
Naturwissenschaften ; 97(10): 861-81, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20838756

RESUMO

The phenomenon called cold fusion has been studied for the last 21 years since its discovery by Profs. Fleischmann and Pons in 1989. The discovery was met with considerable skepticism, but supporting evidence has accumulated, plausible theories have been suggested, and research is continuing in at least eight countries. This paper provides a brief overview of the major discoveries and some of the attempts at an explanation. The evidence supports the claim that a nuclear reaction between deuterons to produce helium can occur in special materials without application of high energy. This reaction is found to produce clean energy at potentially useful levels without the harmful byproducts normally associated with a nuclear process. Various requirements of a model are examined.


Assuntos
Deutério , Fusão Nuclear , Trítio , Calorimetria , Temperatura Baixa , Eletrodos , Paládio , Termodinâmica
16.
J Environ Monit ; 12(9): 1756-64; author reply 1765-70, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20689899

RESUMO

Cold fusion researchers have accumulated a large body of anomalous results over the last 20 years that they claim proves a new, mysterious nuclear reaction is active in systems they study. Krivit and Marwan (J. Environ. Monit., 2009, 11, 1731) give a brief and wholly positive view of this body of research. Unfortunately, cold fusion researchers routinely ignore conventional explanations of their observations, and claim much greater than the real accuracy and precision for their techniques. This paper attempts to equally briefly address those aspects of the field with the intent of providing a balanced view of the field, and to establish some criteria for subsequent publications in this arena.


Assuntos
Fusão Nuclear , Calorimetria , Polietilenoglicóis/química , Projetos de Pesquisa
17.
PLoS One ; 15(11): e0235725, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33147262

RESUMO

Sex is a hallmark of eukaryotes but its evolution in microbial eukaryotes is poorly elucidated. Recent genomic studies revealed microbial eukaryotes possess a genetic toolkit necessary for sexual reproduction. However, the mechanism of sexual development in a majority of microbial eukaryotes including amoebozoans is poorly characterized. The major hurdle in studying sex in microbial eukaryotes is a lack of observational evidence, primarily due to its cryptic nature. In this study, we used a tractable fusing amoeba, Cochliopodium, to investigate sexual development using stage-specific Differential Gene Expression (DGE) and cytological analyses. Both DGE and cytological results showed that most of the meiosis and sex-related genes are upregulated in Cochliopodium undergoing fusion in laboratory culture. Relative gene ontology (GO) category representations in unfused and fused cells revealed a functional skew of the fused transcriptome toward DNA metabolism, nucleus and ligases that are suggestive of a commitment to sexual development. However, the GO categories of unfused cells were dominated by metabolic pathways and other processes indicative of a vegetative phase. Our study provides strong evidence that the fused cells represent a sexual stage in Cochliopodium. Our findings have further implications in understanding the evolution and mechanism of inheritance involving multiparents in other eukaryotes with a similar reproductive strategy.


Assuntos
Amoeba/fisiologia , Perfilação da Expressão Gênica/métodos , Reprodução Assexuada/fisiologia , Amoeba/genética , Regulação da Expressão Gênica , Fusão Nuclear , Análise de Sequência de RNA , Análise de Célula Única
18.
Naturwissenschaften ; 96(7): 803-11, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19440686

RESUMO

Recently, there have been many reports of experimental results which indicate occurrences of anomalous deuteron-induced nuclear reactions in metals at low energies. A consistent conventional theoretical description is presented for anomalous low-energy deuteron-induced nuclear reactions in metal. The theory is based on the Bose-Einstein condensate (BEC) state occupied by deuterons trapped in a micro/nano-scale metal grain or particle. The theory is capable of explaining most of the experimentally observed results and also provides theoretical predictions, which can be tested experimentally. Scalabilities of the observed effects are discussed based on theoretical predictions.


Assuntos
Partículas Elementares , Metais/química , Modelos Teóricos , Física Nuclear , Deutério/química , Fenômenos Mecânicos , Fusão Nuclear , Reatores Nucleares , Valor Preditivo dos Testes , Teoria Quântica
19.
PLoS One ; 14(2): e0211963, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30735548

RESUMO

In the era of big science, countries allocate big research and development budgets to large scientific facilities that boost collaboration and research capability. A nuclear fusion device called the "tokamak" is a source of great interest for many countries because it ideally generates sustainable energy expected to solve the energy crisis in the future. Here, to explore the scientific effects of tokamaks, we map a country's research capability in nuclear fusion research with normalized revealed comparative advantage on five topical clusters-material, plasma, device, diagnostics, and simulation-detected through a dynamic topic model. Our approach captures not only the growth of China, India, and the Republic of Korea but also the decline of Canada, Japan, Sweden, and the Netherlands. Time points of their rise and fall are related to tokamak operation, highlighting the importance of large facilities in big science. The gravity model points out that two countries collaborate less in device, diagnostics, and plasma research if they have comparative advantages in different topics. This relation is a unique feature of nuclear fusion compared to other science fields. Our results can be used and extended when building national policies for big science.


Assuntos
Fusão Nuclear , Física Nuclear/instrumentação , Pesquisa , Bibliografias como Assunto , Canadá , China , Humanos , Índia , Estudos Interdisciplinares , Japão , Modelos Teóricos , Países Baixos , Energia Renovável , República da Coreia , Suécia
20.
Radiat Prot Dosimetry ; 184(3-4): 324-327, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31038693

RESUMO

Deuterium plasma operations using a large fusion test device have been carried out since 2017 at the National Institute for Fusion Science. A small amount of tritium was produced by the fusion reaction, d(d, p)t. Then, a part of the tritium was released into the environment. Thus, monitoring the level of tritium in the environment around the fusion test facility is important. This is done before starting the deuterium plasma experiment. The environmental tritium concentrations indicated that they are at background levels in Japan. After starting the deuterium plasma experiment, the environmental tritium around the fusion test facility was within the range of environmental variation. This suggests that there was no impact of tritium on the environment during the first deuterium plasma experimental campaign.


Assuntos
Poluentes Atmosféricos/análise , Deutério/análise , Fusão Nuclear , Reatores Nucleares , Monitoramento de Radiação/instrumentação , Trítio/análise , Humanos , Japão
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