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  • 1
    Publication Date: 2013-08-09
    Description: The cyclic AMP (cAMP)-dependent catabolite repression effect in Escherichia coli is among the most intensely studied regulatory processes in biology. However, the physiological function(s) of cAMP signalling and its molecular triggers remain elusive. Here we use a quantitative physiological approach to show that cAMP signalling tightly coordinates the expression of catabolic proteins with biosynthetic and ribosomal proteins, in accordance with the cellular metabolic needs during exponential growth. The expression of carbon catabolic genes increased linearly with decreasing growth rates upon limitation of carbon influx, but decreased linearly with decreasing growth rate upon limitation of nitrogen or sulphur influx. In contrast, the expression of biosynthetic genes showed the opposite linear growth-rate dependence as the catabolic genes. A coarse-grained mathematical model provides a quantitative framework for understanding and predicting gene expression responses to catabolic and anabolic limitations. A scheme of integral feedback control featuring the inhibition of cAMP signalling by metabolic precursors is proposed and validated. These results reveal a key physiological role of cAMP-dependent catabolite repression: to ensure that proteomic resources are spent on distinct metabolic sectors as needed in different nutrient environments. Our findings underscore the power of quantitative physiology in unravelling the underlying functions of complex molecular signalling networks.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4038431/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4038431/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉You, Conghui -- Okano, Hiroyuki -- Hui, Sheng -- Zhang, Zhongge -- Kim, Minsu -- Gunderson, Carl W -- Wang, Yi-Ping -- Lenz, Peter -- Yan, Dalai -- Hwa, Terence -- R01 GM095903/GM/NIGMS NIH HHS/ -- England -- Nature. 2013 Aug 15;500(7462):301-6. doi: 10.1038/nature12446. Epub 2013 Aug 7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California at San Diego, La Jolla, California 92093-0374, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23925119" target="_blank"〉PubMed〈/a〉
    Keywords: Cyclic AMP/*metabolism ; Escherichia coli/*genetics/*metabolism ; Escherichia coli Proteins/*genetics/*metabolism ; *Gene Expression Regulation, Bacterial ; Models, Biological ; *Proteome ; *Signal Transduction
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 2013-05-07
    Description: Semaphorin 3A (Sema3A) is a diffusible axonal chemorepellent that has an important role in axon guidance. Previous studies have demonstrated that Sema3a(-/-) mice have multiple developmental defects due to abnormal neuronal innervations. Here we show in mice that Sema3A is abundantly expressed in bone, and cell-based assays showed that Sema3A affected osteoblast differentiation in a cell-autonomous fashion. Accordingly, Sema3a(-/-) mice had a low bone mass due to decreased bone formation. However, osteoblast-specific Sema3A-deficient mice (Sema3acol1(-/-) and Sema3aosx(-/-) mice) had normal bone mass, even though the expression of Sema3A in bone was substantially decreased. In contrast, mice lacking Sema3A in neurons (Sema3asynapsin(-/-) and Sema3anestin(-/-) mice) had low bone mass, similar to Sema3a(-/-) mice, indicating that neuron-derived Sema3A is responsible for the observed bone abnormalities independent of the local effect of Sema3A in bone. Indeed, the number of sensory innervations of trabecular bone was significantly decreased in Sema3asynapsin(-/-) mice, whereas sympathetic innervations of trabecular bone were unchanged. Moreover, ablating sensory nerves decreased bone mass in wild-type mice, whereas it did not reduce the low bone mass in Sema3anestin(-/-) mice further, supporting the essential role of the sensory nervous system in normal bone homeostasis. Finally, neuronal abnormalities in Sema3a(-/-) mice, such as olfactory development, were identified in Sema3asynasin(-/-) mice, demonstrating that neuron-derived Sema3A contributes to the abnormal neural development seen in Sema3a(-/-) mice, and indicating that Sema3A produced in neurons regulates neural development in an autocrine manner. This study demonstrates that Sema3A regulates bone remodelling indirectly by modulating sensory nerve development, but not directly by acting on osteoblasts.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fukuda, Toru -- Takeda, Shu -- Xu, Ren -- Ochi, Hiroki -- Sunamura, Satoko -- Sato, Tsuyoshi -- Shibata, Shinsuke -- Yoshida, Yutaka -- Gu, Zirong -- Kimura, Ayako -- Ma, Chengshan -- Xu, Cheng -- Bando, Waka -- Fujita, Koji -- Shinomiya, Kenichi -- Hirai, Takashi -- Asou, Yoshinori -- Enomoto, Mitsuhiro -- Okano, Hideyuki -- Okawa, Atsushi -- Itoh, Hiroshi -- NS065048/NS/NINDS NIH HHS/ -- England -- Nature. 2013 May 23;497(7450):490-3. doi: 10.1038/nature12115. Epub 2013 May 5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Internal Medicine, School of Medicine, Keio University, Shinanomachi 35, Shinjyuku-ku, Tokyo 160-8582, Japan.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23644455" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Bone Remodeling ; Bone and Bones/anatomy & histology/*innervation/*metabolism ; Cell Differentiation ; Cells, Cultured ; Female ; Male ; Mice ; Organ Size ; Osteoblasts/cytology/metabolism ; Semaphorin-3A/deficiency/genetics/*metabolism ; Sensory Receptor Cells/cytology/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 3
    Publication Date: 2015-12-04
    Description: Overflow metabolism refers to the seemingly wasteful strategy in which cells use fermentation instead of the more efficient respiration to generate energy, despite the availability of oxygen. Known as the Warburg effect in the context of cancer growth, this phenomenon occurs ubiquitously for fast-growing cells, including bacteria, fungi and mammalian cells, but its origin has remained unclear despite decades of research. Here we study metabolic overflow in Escherichia coli, and show that it is a global physiological response used to cope with changing proteomic demands of energy biogenesis and biomass synthesis under different growth conditions. A simple model of proteomic resource allocation can quantitatively account for all of the observed behaviours, and accurately predict responses to new perturbations. The key hypothesis of the model, that the proteome cost of energy biogenesis by respiration exceeds that by fermentation, is quantitatively confirmed by direct measurement of protein abundances via quantitative mass spectrometry.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Basan, Markus -- Hui, Sheng -- Okano, Hiroyuki -- Zhang, Zhongge -- Shen, Yang -- Williamson, James R -- Hwa, Terence -- R01-GM109069/GM/NIGMS NIH HHS/ -- England -- Nature. 2015 Dec 3;528(7580):99-104. doi: 10.1038/nature15765.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California at San Diego, La Jolla, California 92093-0374, USA. ; Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland. ; Section of Molecular Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093, USA. ; Department of Integrative Structural and Computational Biology, Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA. ; Institute for Theoretical Studies, ETH Zurich, 8092 Zurich, Switzerland.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26632588" target="_blank"〉PubMed〈/a〉
    Keywords: Acetic Acid/metabolism ; Biomass ; Cell Respiration ; Energy Metabolism ; Escherichia coli/growth & development/*metabolism ; Escherichia coli Proteins/*metabolism ; Fermentation ; Mass Spectrometry ; Models, Biological ; Neoplasms/metabolism/pathology ; Oxygen/metabolism ; Proteome/*metabolism ; Proteomics
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 4
    Publication Date: 2013-11-30
    Description: To predict the emergence of antibiotic resistance, quantitative relations must be established between the fitness of drug-resistant organisms and the molecular mechanisms conferring resistance. These relations are often unknown and may depend on the state of bacterial growth. To bridge this gap, we have investigated Escherichia coli strains expressing resistance to translation-inhibiting antibiotics. We show that resistance expression and drug inhibition are linked in a positive feedback loop arising from an innate, global effect of drug-inhibited growth on gene expression. A quantitative model of bacterial growth based on this innate feedback accurately predicts the rich phenomena observed: a plateau-shaped fitness landscape, with an abrupt drop in the growth rates of cultures at a threshold drug concentration, and the coexistence of growing and nongrowing populations, that is, growth bistability, below the threshold.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059556/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4059556/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Deris, J Barrett -- Kim, Minsu -- Zhang, Zhongge -- Okano, Hiroyuki -- Hermsen, Rutger -- Groisman, Alexander -- Hwa, Terence -- 1 U54 CA143803/CA/NCI NIH HHS/ -- R01 GM095903/GM/NIGMS NIH HHS/ -- R01-GM095903/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Nov 29;342(6162):1237435. doi: 10.1126/science.1237435.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, University of California at San Diego, La Jolla, CA 92093-0374, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24288338" target="_blank"〉PubMed〈/a〉
    Keywords: *Adaptation, Physiological ; Chloramphenicol/metabolism/pharmacology ; Chloramphenicol O-Acetyltransferase/biosynthesis ; *Drug Resistance, Bacterial ; Escherichia coli/*drug effects/genetics/*growth & development ; Gene Expression Regulation, Bacterial/drug effects ; *Genetic Fitness ; Models, Biological ; Protein Biosynthesis/drug effects ; Protein Synthesis Inhibitors/metabolism/*pharmacology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 2011-04-08
    Description: Regulatory mechanisms governing the sequence from progenitor cell proliferation to neuronal migration during corticogenesis are poorly understood. Here we report that phosphorylation of DISC1, a major susceptibility factor for several mental disorders, acts as a molecular switch from maintaining proliferation of mitotic progenitor cells to activating migration of postmitotic neurons in mice. Unphosphorylated DISC1 regulates canonical Wnt signalling via an interaction with GSK3beta, whereas specific phosphorylation at serine 710 (S710) triggers the recruitment of Bardet-Biedl syndrome (BBS) proteins to the centrosome. In support of this model, loss of BBS1 leads to defects in migration, but not proliferation, whereas DISC1 knockdown leads to deficits in both. A phospho-dead mutant can only rescue proliferation, whereas a phospho-mimic mutant rescues exclusively migration defects. These data highlight a dual role for DISC1 in corticogenesis and indicate that phosphorylation of this protein at S710 activates a key developmental switch.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088774/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088774/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ishizuka, Koko -- Kamiya, Atsushi -- Oh, Edwin C -- Kanki, Hiroaki -- Seshadri, Saurav -- Robinson, Jon F -- Murdoch, Hannah -- Dunlop, Allan J -- Kubo, Ken-ichiro -- Furukori, Keiko -- Huang, Beverly -- Zeledon, Mariela -- Hayashi-Takagi, Akiko -- Okano, Hideyuki -- Nakajima, Kazunori -- Houslay, Miles D -- Katsanis, Nicholas -- Sawa, Akira -- DK-072301/DK/NIDDK NIH HHS/ -- DK-075972/DK/NIDDK NIH HHS/ -- G0600765/Medical Research Council/United Kingdom -- HD-04260/HD/NICHD NIH HHS/ -- MH-069853/MH/NIMH NIH HHS/ -- MH-084018/MH/NIMH NIH HHS/ -- MH-085226/MH/NIMH NIH HHS/ -- MH-088753/MH/NIMH NIH HHS/ -- MH-091230/MH/NIMH NIH HHS/ -- R01 DK072301/DK/NIDDK NIH HHS/ -- R01 DK075972/DK/NIDDK NIH HHS/ -- R01 DK075972-06/DK/NIDDK NIH HHS/ -- R01 HD042601/HD/NICHD NIH HHS/ -- R01 HD042601-10/HD/NICHD NIH HHS/ -- R01 MH091230/MH/NIMH NIH HHS/ -- R01 MH092443/MH/NIMH NIH HHS/ -- England -- Nature. 2011 May 5;473(7345):92-6. doi: 10.1038/nature09859. Epub 2011 Apr 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21471969" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; COS Cells ; Cell Movement/genetics ; Cell Proliferation ; Cercopithecus aethiops ; Cerebral Cortex/cytology/*embryology/physiology ; Gene Knockdown Techniques ; Glycogen Synthase Kinase 3/metabolism ; HEK293 Cells ; Humans ; Mice ; Microtubule-Associated Proteins/genetics/metabolism ; *Nerve Tissue Proteins/genetics/metabolism ; Neurons/*cytology/metabolism/*physiology ; PC12 Cells ; Phosphorylation ; Protein Binding ; Rats ; Signal Transduction ; Stem Cells/*cytology ; Wnt Proteins/metabolism ; beta Catenin/metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 6
    Publication Date: 2014-02-18
    Description: The human neocortex has numerous specialized functional areas whose formation is poorly understood. Here, we describe a 15-base pair deletion mutation in a regulatory element of GPR56 that selectively disrupts human cortex surrounding the Sylvian fissure bilaterally including "Broca's area," the primary language area, by disrupting regional GPR56 expression and blocking RFX transcription factor binding. GPR56 encodes a heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor required for normal cortical development and is expressed in cortical progenitor cells. GPR56 expression levels regulate progenitor proliferation. GPR56 splice forms are highly variable between mice and humans, and the regulatory element of gyrencephalic mammals directs restricted lateral cortical expression. Our data reveal a mechanism by which control of GPR56 expression pattern by multiple alternative promoters can influence stem cell proliferation, gyral patterning, and, potentially, neocortex evolution.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480613/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉   〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480613/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bae, Byoung-Il -- Tietjen, Ian -- Atabay, Kutay D -- Evrony, Gilad D -- Johnson, Matthew B -- Asare, Ebenezer -- Wang, Peter P -- Murayama, Ayako Y -- Im, Kiho -- Lisgo, Steven N -- Overman, Lynne -- Sestan, Nenad -- Chang, Bernard S -- Barkovich, A James -- Grant, P Ellen -- Topcu, Meral -- Politsky, Jeffrey -- Okano, Hideyuki -- Piao, Xianhua -- Walsh, Christopher A -- 2R01NS035129/NS/NINDS NIH HHS/ -- G0700089/Medical Research Council/United Kingdom -- GR082557/Wellcome Trust/United Kingdom -- HHSN275200900011C/PHS HHS/ -- N01-HD-9-0011/HD/NICHD NIH HHS/ -- R01 NS035129/NS/NINDS NIH HHS/ -- U01 MH081896/MH/NIMH NIH HHS/ -- U01MH081896/MH/NIMH NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2014 Feb 14;343(6172):764-8. doi: 10.1126/science.1244392.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Genetics and Genomics, Manton Center for Orphan Disease, and Howard Hughes Medical Institute, Boston Children's Hospital, Broad Institute of MIT and Harvard, and Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24531968" target="_blank"〉PubMed〈/a〉
    Keywords: *Alternative Splicing ; Animals ; Base Sequence ; Biological Evolution ; Body Patterning/*genetics ; Cats ; Cell Proliferation ; Cerebral Cortex/anatomy & histology/cytology/*embryology ; Codon, Nonsense ; Frontal Lobe/anatomy & histology/cytology/embryology ; Genetic Variation ; Haplotypes ; Humans ; Mice ; Molecular Sequence Data ; Neural Stem Cells/cytology/*physiology ; Pedigree ; Promoter Regions, Genetic/genetics ; Receptors, G-Protein-Coupled/*genetics ; Sequence Deletion
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Abstract: Adaptation to hypoxia depends on a conserved alpha/beta heterodimeric transcription factor called Hypoxia Inducible Factor (HIF), whose alpha-subunit is regulated by oxygen through different concurrent mechanisms. In this study, we have identified the RNA binding protein dMusashi, as a negative regulator of the fly HIF homologue Sima. Genetic interaction assays suggested that dMusashi participates of the HIF pathway, and molecular studies carried out in Drosophila cell cultures showed that dMusashi recognizes a Musashi Binding Element in the 3' UTR of the HIFalpha transcript, thereby mediating its translational repression in normoxia. In hypoxic conditions dMusashi is downregulated, lifting HIFalpha repression and contributing to trigger HIF-dependent gene expression. Analysis performed in mouse brains revealed that murine Msi1 protein physically interacts with HIF-1alpha transcript, suggesting that the regulation of HIF by Msi might be conserved in mammalian systems. Thus, Musashi is a novel regulator of HIF that inhibits responses to hypoxia specifically when oxygen is available.
    Type of Publication: Journal article published
    PubMed ID: 27141964
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  • 8
    Keywords: proliferation ; IN-VIVO ; DIFFERENTIATION ; MICE ; COLORECTAL-CANCER ; PROGENITOR CELLS ; beta-catenin ; APC ; WNT/BETA-CATENIN ; INTESTINAL STEM-CELLS
    Abstract: There is a gradient of beta-catenin expression along the colonic crypt axis with the highest levels at the crypt bottom. In addition, colorectal cancers show a heterogeneous subcellular pattern of beta-catenin accumulation. However, it remains unclear whether different levels of Wnt signalling exert distinct roles in the colonic epithelium. Here, we investigated the dose-dependent effect of canonical Wnt activation on colonic epithelial differentiation by controlling the expression levels of stabilised beta-catenin using a doxycycline-inducible transgenic system in mice. We show that elevated levels of Wnt signalling induce the amplification of Lgr5+ cells, which is accompanied by crypt fission and a reduction in cell proliferation among progenitor cells. By contrast, lower levels of beta-catenin induction enhance cell proliferation rates of epithelial progenitors without affecting crypt fission rates. Notably, slow-cycling cells produced by beta-catenin activation exhibit activation of Notch signalling. Consistent with the interpretation that the combination of Notch and Wnt signalling maintains crypt cells in a low proliferative state, the treatment of beta-catenin-expressing mice with a Notch inhibitor turned such slow-cycling cells into actively proliferating cells. Our results indicate that the activation of the canonical Wnt signalling pathway is sufficient for de novo crypt formation, and suggest that different levels of canonical Wnt activations, in cooperation with Notch signalling, establish a hierarchy of slower-cycling stem cells and faster-cycling progenitor cells characteristic for the colonic epithelium.
    Type of Publication: Journal article published
    PubMed ID: 23222438
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  • 9
    ISSN: 0378-1119
    Keywords: Pelizaeus-Merzbacher disease ; RNase A and T1 mapping ; X-linked ; myelin deficiency ; oligodendrocytes ; phage vectors ; recombinant DNA
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0630
    Keywords: 82.50 ; 81.60 ; 82.30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Studies have been made of poly- and single Si etching induced by excimer-laser irradiation of the silicon surfaces in halogenated gases. Etching was investigated for different conduction types, impurity concentrations and crystallographic planes. Chlorine atoms accept electrons generated in photoexcited, undoped p-type Si, thus becoming negative ions which are pulled into the Si. However, the n+-type Si is etched spontaneously by Cl− as a result of the availability of conduction electrons. Fluorine atoms, with the highest electronegativity, take in electrons independent of whether the material is n- or p-type. And thus, the easy F− ion penetration into Si causes spontaneous etching in both types. New anisotropic etching for n+ poly-Si is investigated because of its importance to microfabrication technology. Methyl methacrylate (MMA) gas, which reacts with Cl atoms, produces a deposition film on the n+ poly-Si surface. The surface, from which the film is removed by KrF (5 eV) laser irradiation, is etched by Cl atoms, while the film remains on the side wall to protect undercutting. However, with the higher photon energy for the ArF (6.4 eV) laser, the Si-OH bonds are broken and electron traps are formed. These electrontrapping centers are easily annealed out in comparison to the plasma-induced centers. Pattern transfer etching for n+ poly-Si has been realized using reflective optics. The problems involved in obtaining finer resolution etching are discussed.
    Type of Medium: Electronic Resource
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