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Ferrari A, Whang E, Xiao X, Kennelly JP, Romartinez-Alonso B, Mack JJ, Weston T, Chen K, Kim Y, Tol MJ, Bideyan L, Nguyen A, Gao Y, Cui L, Bedard AH, Sandhu J, Lee SD, Fairall L, Williams KJ, Song W, Munguia P, Russell RA, Martin MG, Jung ME, Jiang H, Schwabe JWR, Young SG, Tontonoz P. Aster-dependent nonvesicular transport facilitates dietary cholesterol uptake. Science 2023; 382:eadf0966. [PMID: 37943936 DOI: 10.1126/science.adf0966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 09/27/2023] [Indexed: 11/12/2023]
Abstract
Intestinal absorption is an important contributor to systemic cholesterol homeostasis. Niemann-Pick C1 Like 1 (NPC1L1) assists in the initial step of dietary cholesterol uptake, but how cholesterol moves downstream of NPC1L1 is unknown. We show that Aster-B and Aster-C are critical for nonvesicular cholesterol movement in enterocytes. Loss of NPC1L1 diminishes accessible plasma membrane (PM) cholesterol and abolishes Aster recruitment to the intestinal brush border. Enterocytes lacking Asters accumulate PM cholesterol and show endoplasmic reticulum cholesterol depletion. Aster-deficient mice have impaired cholesterol absorption and are protected against diet-induced hypercholesterolemia. Finally, the Aster pathway can be targeted with a small-molecule inhibitor to manipulate cholesterol uptake. These findings identify the Aster pathway as a physiologically important and pharmacologically tractable node in dietary lipid absorption.
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Affiliation(s)
- Alessandra Ferrari
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Emily Whang
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Pediatric Gastroenterology, Hepatology, and Nutrition, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xu Xiao
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - John P Kennelly
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - Julia J Mack
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Thomas Weston
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kai Chen
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Youngjae Kim
- Department of Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Marcus J Tol
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Lara Bideyan
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander Nguyen
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine
| | - Yajing Gao
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Liujuan Cui
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander H Bedard
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jaspreet Sandhu
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Stephen D Lee
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Louise Fairall
- Institute for Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Kevin J Williams
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
- UCLA Lipidomics Core, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wenxin Song
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Priscilla Munguia
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Robert A Russell
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Martin G Martin
- Pediatric Gastroenterology, Hepatology, and Nutrition, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael E Jung
- Department of Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Haibo Jiang
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - John W R Schwabe
- Institute for Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Stephen G Young
- Department of Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
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Ferrari A, Whang E, Xiao X, Kennelly JP, Romartinez-Alonso B, Mack JJ, Weston T, Chen K, Kim Y, Tol MJ, Bideyan L, Nguyen A, Gao Y, Cui L, Bedard AH, Sandhu J, Lee SD, Fairall L, Williams KJ, Song W, Munguia P, Russell RA, Martin MG, Jung ME, Jiang H, Schwabe JWR, Young SG, Tontonoz P. Aster-dependent non-vesicular transport facilitates dietary cholesterol uptake. bioRxiv 2023:2023.07.07.548168. [PMID: 37503112 PMCID: PMC10369906 DOI: 10.1101/2023.07.07.548168] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Intestinal cholesterol absorption is an important contributor to systemic cholesterol homeostasis. Niemann-Pick C1 Like 1 (NPC1L1), the target of the drug ezetimibe (EZ), assists in the initial step of dietary cholesterol uptake. However, how cholesterol moves downstream of NPC1L1 is unknown. Here we show that Aster-B and Aster-C are critical for non-vesicular cholesterol movement in enterocytes, bridging NPC1L1 at the plasma membrane (PM) and ACAT2 in the endoplasmic reticulum (ER). Loss of NPC1L1 diminishes accessible PM cholesterol in enterocytes and abolishes Aster recruitment to the intestinal brush border. Enterocytes lacking Asters accumulate cholesterol at the PM and display evidence of ER cholesterol depletion, including decreased cholesterol ester stores and activation of the SREBP-2 transcriptional pathway. Aster-deficient mice have impaired cholesterol absorption and are protected against diet-induced hypercholesterolemia. Finally, we show that the Aster pathway can be targeted with a small molecule inhibitor to manipulate dietary cholesterol uptake. These findings identify the Aster pathway as a physiologically important and pharmacologically tractable node in dietary lipid absorption. One-Sentence Summary Identification of a targetable pathway for regulation of dietary cholesterol absorption.
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Song W, Yang Y, Heizer P, Tu Y, Weston TA, Kim JR, Munguia P, Jung H, Fong JLC, Tran C, Ploug M, Beigneux AP, Young SG, Fong LG. Intracapillary LPL levels in brown adipose tissue, visualized with an antibody-based approach, are regulated by ANGPTL4 at thermoneutral temperatures. Proc Natl Acad Sci U S A 2023; 120:e2219833120. [PMID: 36787365 PMCID: PMC9974459 DOI: 10.1073/pnas.2219833120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/18/2023] [Indexed: 02/15/2023] Open
Abstract
Lipoprotein lipase (LPL) is secreted into the interstitial spaces by parenchymal cells and then transported into capillaries by GPIHBP1. LPL carries out the lipolytic processing of triglyceride (TG)-rich lipoproteins (TRLs), but the tissue-specific regulation of LPL is incompletely understood. Plasma levels of TG hydrolase activity after heparin injection are often used to draw inferences about intravascular LPL levels, but the validity of these inferences is unclear. Moreover, plasma TG hydrolase activity levels are not helpful for understanding LPL regulation in specific tissues. Here, we sought to elucidate LPL regulation under thermoneutral conditions (30 °C). To pursue this objective, we developed an antibody-based method to quantify (in a direct fashion) LPL levels inside capillaries. At 30 °C, intracapillary LPL levels fell sharply in brown adipose tissue (BAT) but not heart. The reduced intracapillary LPL levels were accompanied by reduced margination of TRLs along capillaries. ANGPTL4 expression in BAT increased fourfold at 30 °C, suggesting a potential explanation for the lower intracapillary LPL levels. Consistent with that idea, Angptl4 deficiency normalized both LPL levels and TRL margination in BAT at 30 °C. In Gpihbp1-/- mice housed at 30 °C, we observed an ANGPTL4-dependent decrease in LPL levels within the interstitial spaces of BAT, providing in vivo proof that ANGPTL4 regulates LPL levels before LPL transport into capillaries. In conclusion, our studies have illuminated intracapillary LPL regulation under thermoneutral conditions. Our approaches will be useful for defining the impact of genetic variation and metabolic disease on intracapillary LPL levels and TRL processing.
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Affiliation(s)
- Wenxin Song
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Ye Yang
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Patrick Heizer
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Yiping Tu
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Thomas A. Weston
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Joonyoung R. Kim
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Priscilla Munguia
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Hyesoo Jung
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Jared L.-C. Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Caitlyn Tran
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Michael Ploug
- Finsen Laboratory, RigshospitaletDK-2200Copenhagen N, Denmark
- Biotech Research and Innovation Centre, University of CopenhagenDK-220Copenhagen N, Denmark
| | - Anne P. Beigneux
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Stephen G. Young
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA90095
| | - Loren G. Fong
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA90095
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Song W, Beigneux AP, Winther AML, Kristensen KK, Grønnemose AL, Yang Y, Tu Y, Munguia P, Morales J, Jung H, de Jong PJ, Jung CJ, Miyashita K, Kimura T, Nakajima K, Murakami M, Birrane G, Jiang H, Tontonoz P, Ploug M, Fong LG, Young SG. Electrostatic sheathing of lipoprotein lipase is essential for its movement across capillary endothelial cells. J Clin Invest 2022; 132:157500. [PMID: 35229724 PMCID: PMC8884915 DOI: 10.1172/jci157500] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/19/2022] [Indexed: 12/18/2022] Open
Abstract
GPIHBP1, an endothelial cell (EC) protein, captures lipoprotein lipase (LPL) within the interstitial spaces (where it is secreted by myocytes and adipocytes) and transports it across ECs to its site of action in the capillary lumen. GPIHBP1’s 3-fingered LU domain is required for LPL binding, but the function of its acidic domain (AD) has remained unclear. We created mutant mice lacking the AD and found severe hypertriglyceridemia. As expected, the mutant GPIHBP1 retained the capacity to bind LPL. Unexpectedly, however, most of the GPIHBP1 and LPL in the mutant mice was located on the abluminal surface of ECs (explaining the hypertriglyceridemia). The GPIHBP1-bound LPL was trapped on the abluminal surface of ECs by electrostatic interactions between the large basic patch on the surface of LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the surface of ECs. GPIHBP1 trafficking across ECs in the mutant mice was normalized by disrupting LPL-HSPG electrostatic interactions with either heparin or an AD peptide. Thus, GPIHBP1’s AD plays a crucial function in plasma triglyceride metabolism; it sheathes LPL’s basic patch on the abluminal surface of ECs, thereby preventing LPL-HSPG interactions and freeing GPIHBP1-LPL complexes to move across ECs to the capillary lumen.
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Affiliation(s)
- Wenxin Song
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Anne P Beigneux
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Anne-Marie L Winther
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Kristian K Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Anne L Grønnemose
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Ye Yang
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Yiping Tu
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Priscilla Munguia
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Jazmin Morales
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Hyesoo Jung
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, California, USA
| | - Cris J Jung
- Children's Hospital Oakland Research Institute, Oakland, California, USA
| | - Kazuya Miyashita
- Department of Clinical Laboratory Medicine, Gunma University, Graduate School of Medicine, Maebashi, Gunma, Japan.,Immuno-Biological Laboratories (IBL), Fujioka, Gunma, Japan
| | - Takao Kimura
- Department of Clinical Laboratory Medicine, Gunma University, Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Katsuyuki Nakajima
- Department of Clinical Laboratory Medicine, Gunma University, Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Masami Murakami
- Department of Clinical Laboratory Medicine, Gunma University, Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Gabriel Birrane
- Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Haibo Jiang
- Department of Chemistry, The University of Hong Kong, Hong Kong
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Loren G Fong
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Stephen G Young
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California, USA.,Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
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Munguia P, Caramelo R, Rubio MV, Sahdalá L, Arnaudas L, Paul J, Blasco Á, Lou LM, Aladren MJ, Sanjuan A, Gutierrez-Dalmau A. Pre-Transplant Assessment of Vascular Calcification as a Risk Factor of Mortality, Graft Loss, and Cardiovascular Events in Renal Transplant Recipients. Transplant Proc 2016; 47:2368-70. [PMID: 26518929 DOI: 10.1016/j.transproceed.2015.08.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Vascular calcification (VC) is known as an independent predictor of mortality in patients undergoing hemodialysis; nevertheless, there is a lack of studies about the impact of vascular calcification in renal transplant recipients, and none of them use the Kauppila Index (KI) as a predictor of patient and graft prognosis. METHODS We conducted an observational, retrospective study of 119 renal transplants, evaluating abdominal aortic calcifications (L4-S1) with the KI. We established 2 categories: absence (KI = 0-2) and presence (KI = 3-24) of VCs before transplantation. We analyzed the impact of calcification in graft and patient survival, new-onset diabetes mellitus, hypertension, cardiovascular events, renal function, and mineral metabolism. RESULTS VCs were observed in 50 patients (42%) before renal transplantation. Patients with VCs were older, but no statistical differences were found in the pre-transplant study between sex, diabetes, body mass index, and cardiovascular events. We found a major patient survival (limited to first 2 years after transplantation), graft survival, and death-censored graft survival in those without VCs (P = .037, P = .015, and P = .023, respectively). In line with results, a higher incidence of major cardiovascular events (MACE) and cardiovascular death was observed in the group with preexisting calcification (P = .016/P = .019). In the multivariable analysis, VCs were not an independent predictor for graft loss, death-censored graft loss, or major cardiovascular events. CONCLUSIONS Simple evaluation of VCs with the use of the KI at the time of transplantation relates with graft and patient survival and with MACE after renal transplantation.
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Affiliation(s)
- P Munguia
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - R Caramelo
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - M V Rubio
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - L Sahdalá
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - L Arnaudas
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - J Paul
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - Á Blasco
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - L M Lou
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - M J Aladren
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - A Sanjuan
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain
| | - A Gutierrez-Dalmau
- Department of Nephrology, Hospital Universitario Miguel Servet, Grupo ERC ARAGON, IACS, Zaragoza, Spain.
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Cuellar-Gempeler C, Munguia P. Fiddler crabs (Uca thayeri, Brachyura: Ocypodidae) affect bacterial assemblages in mangrove forest sediments. COMMUNITY ECOL 2013. [DOI: 10.1556/comec.14.2013.1.7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bassous E, Freeman M, Halbout JM, lyer SS, Kesan VP, Munguia P, Pesarcik SF, Williams BL. Characterization of Microporous Silicon Fabricated by Immersion Scanning. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-256-23] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTA novel immersion scanning technique for making microporous silicon has been successfully applied to blank and lithographically patterned Si substrates. The advantages of the method lie in its simplicity, speed and adaptability to large and odd-size substrates. The photoluminescence (PL) spectra of microporous Si show a continuous decrease in intensity between 200K and 2K, but are fully reversible. Thermal desorption spectroscopy on microporous Si shows a classic hydrogen desorption spectrum which coincides with a quenching of the PL intensity. Under constant excitation, a degradation of PL Intensity occurs in oxygen and wet nitrogen but is only partially reversible in dry N2. Microporous Si PN junctions exhibiting normal I-V characteristics have been successfully fabricated with standard Si VLSI processes. Visible light emission under forward bias is detected which increases linearly In Intensity with Input current. This is the first observation of electroluminescence in the visible region from microporous SI PN junctions.
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Canto P, Munguia P, Soderlund D, Castro JJ, Mendez JP. Genetic Analysis in Patients With Kallmann Syndrome: Coexistence of Mutations in Prokineticin Receptor 2 and KAL1. ACTA ACUST UNITED AC 2008; 30:41-5. [DOI: 10.2164/jandrol.108.005314] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Miller TE, Burns JH, Munguia P, Walters EL, Kneitel JM, Richards PM, Mouquet N, Buckley HL. Evaluating Support for the Resource‐Ratio Hypothesis: A Reply to Wilson et al. Am Nat 2007; 169:707-8. [PMID: 17427141 DOI: 10.1086/513110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 09/22/2006] [Indexed: 11/03/2022]
Affiliation(s)
- T E Miller
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA.
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Buckley H, Burns J, Kneitel J, Walters E, Munguia P, Miller E. Small-scale patterns in community structure of Sarracenia purpurea inquilines. COMMUNITY ECOL 2004. [DOI: 10.1556/comec.5.2004.2.6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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