Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Opt Express ; 32(6): 9374-9383, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-38571173

RESUMEN

To realize the high sensitivity polarization sensitive optical coherence tomography (PS-OCT) imaging, a fiber-based full-range depth-encoded swept source PS-OCT (SS-PS-OCT) method is proposed. The two OCT images corresponding to the orthogonal polarized input light are located on the high sensitivity imaging region of the opposite sides relative to the zero optical path difference position. The full-range OCT images can be obtained by implementing the spatial phase modulation in the reference arm. The detection sensitivity of the system was measured experimentally to be 67 dB when the imaging depth approaching to 2 mm. The imaging of the biological tissue verifies that the proposed full-range depth-encoded SS-PS-OCT system has the higher detection sensitivity compared with the conventional depth encoded SS-PS-OCT system. Finally, we demonstrated the full-range high sensitivity phase retardation image of the bovine tendon and skin of human fingertip. The fiber-based full-range depth-encoded SS-PS-OCT method can realize the high sensitivity birefringence imaging in the medical diagnosis scenes with the requirements for long imaging range and high detection sensitivity.

2.
Opt Express ; 31(1): 56-64, 2023 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-36606949

RESUMEN

We introduce a calcium carbonate birefringent crystal into an Er-fiber laser mode-locked by a saturable absorber, where dual-comb ultrashort pulses with orthogonal polarization have been obtained. The two ultrashort pulse trains from the laser exhibit polarization contrast ratios of 30 dB and 20 dB, indicating that the dual-comb mode-locking is due to the polarization-multiplexing mechanism. The dual-comb ultrashort pulses have central wavelengths of 1564.41 nm and 1564.51 nm, and pulse durations of 825 fs and 805 fs respectively. The optical spectra and pulse durations of the asynchronous ultrashort pulses are nearly identical, so that the output of the laser could be directly used for dual-comb applications. Besides, the repetition-rate difference of the two mode-locked pulses is 673 Hz, while its drift is only 0.093 Hz within 2 hours' time. The low drift of the repetition-rate difference manifests the single-cavity dual-comb Er-fiber laser has a high stability and high common-mode noise suppression. At last, we have tested the dual-comb fiber laser in a ranging experiment, where clear interferogram signal can be observed. The experimental results prove that this single-cavity dual-comb Er-fiber laser based on the birefringent crystal and saturable absorber can be a potential source for spectroscopy, optical imaging, absolute distance measurement and other dual-comb applications.

3.
Appl Opt ; 62(4): 989-996, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36821157

RESUMEN

We showed the local polarization properties extraction method for the single incident state, all-single-mode-fiber-based spectral domain polarization-sensitive optical coherence tomography (SD-PS-OCT) system that uses the single linear-in-wavenumber spectral camera. Polarization controllers are used in the single-mode-fiber-based SD-PS-OCT system to provide a compact structure with polarization state stability. The local polarization properties of the birefringent sample are extracted from the cumulative polarization properties iteratively. The reconstructed polarization images demonstrate the local polarization properties extraction ability of the system.

4.
PLoS Genet ; 16(11): e1009119, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-33186356

RESUMEN

Avian eggshell color is an interesting genetic trait. Here, we report that the blue eggshell color of the domestic duck is caused by two cis-regulatory G to A transitions upstream of ABCG2, which encodes an efflux transporter. The juxtaposed blue eggshell allele A-A exhibited higher promoter activity and stronger nuclear protein binding capacity than the white eggshell allele G-G. Transcription factor analysis suggested differential binding capability of CTCF between blue eggshell and white eggshell alleles. Knockdown of CTCF expression significantly decreased the promoter activity of the blue eggshell but not the white eggshell allele. DNA methylation analysis revealed similar high methylation of the region upstream of the CTCF binding sites in both blue-eggshelled and white-eggshelled ducks. However, DNA methylation levels downstream of the binding sites were decreased and 35% lower in blue-eggshelled ducks than in white-eggshelled ducks. Consistent with the in vitro regulatory pattern of causative sites, ABCG2 exhibited higher expression in uteruses of blue-eggshelled ducks and also showed polarized distribution in their endometrial epithelial cells, distributing at the apical surface of endometrial epithelial cells and with orientation toward the uterine cavity, where the eggshell is pigmented. In conclusion, our results suggest that two cis-regulatory SNPs upstream of ABCG2 are the causative mutations for blue eggshells in ducks. The blue eggshell variant up-regulated ABCG2 expression through recruiting CTCF binding, which may function as a barrier element to shield the downstream region from high methylation levels present upstream. ABCG2 was identified as the only candidate causative gene for blue eggshells; it may function as an efflux transporter of biliverdin to the uterine cavity.


Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Patos/genética , Fenotipo , Pigmentación/genética , Regiones Promotoras Genéticas/genética , Alelos , Animales , Color , Cáscara de Huevo/química , Femenino , Estudio de Asociación del Genoma Completo , Mutación , Polimorfismo de Nucleótido Simple , Secuenciación Completa del Genoma
5.
Proc Natl Acad Sci U S A ; 116(11): 5071-5076, 2019 03 12.
Artículo en Inglés | MEDLINE | ID: mdl-30814222

RESUMEN

Drugs that reverse epigenetic silencing, such as the DNA methyltransferase inhibitor (DNMTi) 5-azacytidine (AZA), have profound effects on transcription and tumor cell survival. AZA is an approved drug for myelodysplastic syndromes and acute myeloid leukemia, and is under investigation for different solid malignant tumors. AZA treatment generates self, double-stranded RNA (dsRNA), transcribed from hypomethylated repetitive elements. Self dsRNA accumulation in DNMTi-treated cells leads to type I IFN production and IFN-stimulated gene expression. Here we report that cell death in response to AZA treatment occurs through the 2',5'-oligoadenylate synthetase (OAS)-RNase L pathway. OASs are IFN-induced enzymes that synthesize the RNase L activator 2-5A in response to dsRNA. Cells deficient in RNase L or OAS1 to 3 are highly resistant to AZA, as are wild-type cells treated with a small-molecule inhibitor of RNase L. A small-molecule inhibitor of c-Jun NH2-terminal kinases (JNKs) also antagonizes RNase L-dependent cell death in response to AZA, consistent with a role for JNK in RNase L-induced apoptosis. In contrast, the rates of AZA-induced and RNase L-dependent cell death were increased by transfection of 2-5A, by deficiencies in ADAR1 (which edits and destabilizes dsRNA), PDE12 or AKAP7 (which degrade 2-5A), or by ionizing radiation (which induces IFN-dependent signaling). Finally, OAS1 expression correlates with AZA sensitivity in the NCI-60 set of tumor cell lines, suggesting that the level of OAS1 can be a biomarker for predicting AZA sensitivity of tumor cells. These studies may eventually lead to pharmacologic strategies for regulating the antitumor activity and toxicity of AZA and related drugs.


Asunto(s)
2',5'-Oligoadenilato Sintetasa/metabolismo , Azacitidina/farmacología , Desmetilación del ADN , Endorribonucleasas/metabolismo , Inmunidad Innata , Células A549 , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Muerte Celular/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Humanos , Isoenzimas/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Hidrolasas Diéster Fosfóricas/metabolismo , Radiación Ionizante , Bibliotecas de Moléculas Pequeñas/farmacología
6.
PLoS Genet ; 12(6): e1006071, 2016 06.
Artículo en Inglés | MEDLINE | ID: mdl-27253709

RESUMEN

Muffs and beard (Mb) is a phenotype in chickens where groups of elongated feathers gather from both sides of the face (muffs) and below the beak (beard). It is an autosomal, incomplete dominant phenotype encoded by the Muffs and beard (Mb) locus. Here we use genome-wide association (GWA) analysis, linkage analysis, Identity-by-Descent (IBD) mapping, array-CGH, genome re-sequencing and expression analysis to show that the Mb allele causing the Mb phenotype is a derived allele where a complex structural variation (SV) on GGA27 leads to an altered expression of the gene HOXB8. This Mb allele was shown to be completely associated with the Mb phenotype in nine other independent Mb chicken breeds. The Mb allele differs from the wild-type mb allele by three duplications, one in tandem and two that are translocated to that of the tandem repeat around 1.70 Mb on GGA27. The duplications contain total seven annotated genes and their expression was tested during distinct stages of Mb morphogenesis. A continuous high ectopic expression of HOXB8 was found in the facial skin of Mb chickens, strongly suggesting that HOXB8 directs this regional feather-development. In conclusion, our results provide an interesting example of how genomic structural rearrangements alter the regulation of genes leading to novel phenotypes. Further, it again illustrates the value of utilizing derived phenotypes in domestic animals to dissect the genetic basis of developmental traits, herein providing novel insights into the likely role of HOXB8 in feather development and differentiation.


Asunto(s)
Pollos/genética , Expresión Génica Ectópica/genética , Plumas/crecimiento & desarrollo , Proteínas de Homeodominio/biosíntesis , Proteínas de Homeodominio/genética , Alelos , Animales , Secuencia de Bases , Mapeo Cromosómico , Hibridación Genómica Comparativa , Ligamiento Genético , Estudio de Asociación del Genoma Completo , Hibridación in Situ , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Análisis de Secuencia de ADN
7.
PLoS Genet ; 10(8): e1004576, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25166907

RESUMEN

Silky-feather has been selected and fixed in some breeds due to its unique appearance. This phenotype is caused by a single recessive gene (hookless, h). Here we map the silky-feather locus to chromosome 3 by linkage analysis and subsequently fine-map it to an 18.9 kb interval using the identical by descent (IBD) method. Further analysis reveals that a C to G transversion located upstream of the prenyl (decaprenyl) diphosphate synthase, subunit 2 (PDSS2) gene is causing silky-feather. All silky-feather birds are homozygous for the G allele. The silky-feather mutation significantly decreases the expression of PDSS2 during feather development in vivo. Consistent with the regulatory effect, the C to G transversion is shown to remarkably reduce PDSS2 promoter activity in vitro. We report a new example of feather structure variation associated with a spontaneous mutation and provide new insight into the PDSS2 function.


Asunto(s)
Transferasas Alquil y Aril/genética , Pollos/genética , Plumas/crecimiento & desarrollo , Secuencias Reguladoras de Ácidos Nucleicos , Animales , Cruzamiento , Plumas/metabolismo , Regulación del Desarrollo de la Expresión Génica , Ligamiento Genético , Mutación , Fenotipo , Regiones Promotoras Genéticas
8.
J Biol Chem ; 289(21): 14881-95, 2014 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-24695740

RESUMEN

Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy.


Asunto(s)
Diferenciación Celular/genética , Proteínas Co-Represoras/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Proteínas Proto-Oncogénicas/genética , Transactivadores/genética , Animales , Western Blotting , Células Cultivadas , Inmunoprecipitación de Cromatina , Proteínas Co-Represoras/metabolismo , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Perfilación de la Expresión Génica , Células HEK293 , Humanos , Leucemia/genética , Leucemia/metabolismo , Leucemia/patología , Macrófagos/metabolismo , Ratones , Ratones Noqueados , Mutación , Análisis de Secuencia por Matrices de Oligonucleótidos , Unión Proteica , Proteínas Proto-Oncogénicas/metabolismo , Espectrometría de Masas en Tándem , Transactivadores/metabolismo , Células Tumorales Cultivadas
9.
BMC Genomics ; 16: 851, 2015 Oct 23.
Artículo en Inglés | MEDLINE | ID: mdl-26497311

RESUMEN

BACKGROUND: DNA cytosine methylation is an important epigenetic modification that has significant effects on a variety of biological processes in animals. Avian species hold a crucial position in evolutionary history. In this study, we used whole-genome bisulfite sequencing (MethylC-seq) to generate single base methylation profiles of lungs in two genetically distinct and highly inbred chicken lines (Fayoumi and Leghorn) that differ in genetic resistance to multiple pathogens, and we explored the potential regulatory role of DNA methylation associated with immune response differences between the two chicken lines. METHODS: The MethylC-seq was used to generate single base DNA methylation profiles of Fayoumi and Leghorn birds. In addition, transcriptome profiling using RNA-seq from the same chickens and tissues were obtained to interrogate how DNA methylation regulates gene transcription on a genome-wide scale. RESULTS: The general DNA methylation pattern across different regions of genes was conserved compared to other species except for hyper-methylation of repeat elements, which was not observed in chicken. The methylation level of miRNA and pseudogene promoters was high, which indicates that silencing of these genes may be partially due to promoter hyper-methylation. Interestingly, the promoter regions of more recently evolved genes tended to be more highly methylated, whereas the gene body regions of evolutionarily conserved genes were more highly methylated than those of more recently evolved genes. Immune-related GO (Gene Ontology) terms were significantly enriched from genes within the differentially methylated regions (DMR) between Fayoumi and Leghorn, which implicates DNA methylation as one of the regulatory mechanisms modulating immune response differences between these lines. CONCLUSIONS: This study establishes a single-base resolution DNA methylation profile of chicken lung and suggests a regulatory role of DNA methylation in controlling gene expression and maintaining genome transcription stability. Furthermore, profiling the DNA methylomes of two genetic lines that differ in disease resistance provides a unique opportunity to investigate the potential role of DNA methylation in host disease resistance. Our study provides a foundation for future studies on epigenetic modulation of host immune response to pathogens in chickens.


Asunto(s)
Pollos/genética , Metilación de ADN , Epigénesis Genética , Epigenómica , Transcriptoma , Animales , Composición de Base , Biología Computacional/métodos , Islas de CpG , Epigenómica/métodos , Evolución Molecular , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Genoma , Estudio de Asociación del Genoma Completo/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Pulmón/metabolismo , Anotación de Secuencia Molecular , Regiones Promotoras Genéticas , Seudogenes , Secuencias Repetitivas de Ácidos Nucleicos
11.
PLoS Genet ; 8(6): e1002775, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22761584

RESUMEN

Rose-comb, a classical monogenic trait of chickens, is characterized by a drastically altered comb morphology compared to the single-combed wild-type. Here we show that Rose-comb is caused by a 7.4 Mb inversion on chromosome 7 and that a second Rose-comb allele arose by unequal crossing over between a Rose-comb and wild-type chromosome. The comb phenotype is caused by the relocalization of the MNR2 homeodomain protein gene leading to transient ectopic expression of MNR2 during comb development. We also provide a molecular explanation for the first example of epistatic interaction reported by Bateson and Punnett 104 years ago, namely that walnut-comb is caused by the combined effects of the Rose-comb and Pea-comb alleles. Transient ectopic expression of MNR2 and SOX5 (causing the Pea-comb phenotype) occurs in the same population of mesenchymal cells and with at least partially overlapping expression in individual cells in the comb primordium. Rose-comb has pleiotropic effects, as homozygosity in males has been associated with poor sperm motility. We postulate that this is caused by the disruption of the CCDC108 gene located at one of the inversion breakpoints. CCDC108 is a poorly characterized protein, but it contains a MSP (major sperm protein) domain and is expressed in testis. The study illustrates several characteristic features of the genetic diversity present in domestic animals, including the evolution of alleles by two or more consecutive mutations and the fact that structural changes have contributed to fast phenotypic evolution.


Asunto(s)
Pollos/genética , Inversión Cromosómica/genética , Cresta y Barbas , Proteínas de Homeodominio/genética , Mutación , Animales , Evolución Biológica , Cresta y Barbas/anatomía & histología , Cresta y Barbas/crecimiento & desarrollo , Epistasis Genética , Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio/metabolismo , Masculino , Mesodermo/citología , Fenotipo , Estructura Terciaria de Proteína , Factores de Transcripción SOXD/genética , Factores de Transcripción SOXD/metabolismo , Motilidad Espermática/genética , Motilidad Espermática/fisiología , Testículo/metabolismo
12.
Nat Commun ; 15(1): 1832, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38418452

RESUMEN

PHF6 mutations (PHF6MT) are identified in various myeloid neoplasms (MN). However, little is known about the precise function and consequences of PHF6 in MN. Here we show three main findings in our comprehensive genomic and proteomic study. Firstly, we show a different pattern of genes correlating with PHF6MT in male and female cases. When analyzing male and female cases separately, in only male cases, RUNX1 and U2AF1 are co-mutated with PHF6. In contrast, female cases reveal co-occurrence of ASXL1 mutations and X-chromosome deletions with PHF6MT. Next, proteomics analysis reveals a direct interaction between PHF6 and RUNX1. Both proteins co-localize in active enhancer regions that define the context of lineage differentiation. Finally, we demonstrate a negative prognostic role of PHF6MT, especially in association with RUNX1. The negative effects on survival are additive as PHF6MT cases with RUNX1 mutations have worse outcomes when compared to cases carrying single mutation or wild-type.


Asunto(s)
Leucemia Mieloide Aguda , Neoplasias , Humanos , Masculino , Femenino , Proteínas Represoras/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Proteómica , Mutación , Leucemia Mieloide Aguda/genética
13.
BMC Genomics ; 14: 262, 2013 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-23594354

RESUMEN

BACKGROUND: Copy number variants contribute to genetic variation in birds. Analyses of copy number variants in chicken breeds had focused primarily on those from commercial varieties with nothing known about the occurrence and diversity of copy number variants in locally raised Chinese chicken breeds. To address this deficiency, we characterized copy number variants in 11 chicken breeds and compared the variation among these breeds. RESULTS: We presented a detailed analysis of the copy number variants in locally raised Chinese chicken breeds identified using a customized comparative genomic hybridization array. We identified 833 copy number variants contained within 308 copy number variant regions. The median and mean sizes of the copy number variant regions were 14.6 kb and 35.1 kb, respectively. Of the copy number variant regions, 138 (45%) involved gain of DNA, 159 (52%) involved loss of DNA, and 11 (3%) involved both gain and loss of DNA. Principal component analysis and agglomerative hierarchical clustering revealed the close relatedness of the four locally raised chicken breeds, Shek-Ki, Langshan, Qingyuan partridge, and Wenchang. Biological process enrichment analysis of the copy number variant regions confirmed the greater variation among the four aforementioned varieties than among the seven other breeds studied. CONCLUSION: Our description of the distribution of the copy number variants and comparison of the differences among the copy number variant regions of the 11 chicken breeds supplemented the information available concerning the copy number variants of other Chinese chicken breeds. In addition to its relevance for functional analysis, our results provided the first insight into how chicken breeds can be clustered on the basis of their genomic copy number variation.


Asunto(s)
Pollos/genética , Variaciones en el Número de Copia de ADN , Animales , Cruzamiento , Pollos/clasificación , China , Mapeo Cromosómico , Análisis por Conglomerados , Hibridación Genómica Comparativa , Femenino , Genoma , Masculino , Anotación de Secuencia Molecular , Análisis de Componente Principal
14.
Blood ; 117(24): 6498-508, 2011 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-21518930

RESUMEN

The transcription factor (TF) RUNX1 cooperates with lineage-specifying TFs (eg, PU.1/SPI1) to activate myeloid differentiation genes, such as macrophage and granulocyte macrophage colony-stimulating factor receptors (MCSFR and GMCSFR). Disruption of cooperative gene activation could contribute to aberrant repression of differentiation genes and leukemogenesis initiated by mutations and translocations of RUNX1. To investigate the mechanisms underlying cooperative gene activation, the effects of Runx1 deficiency were examined in an in vitro model of Pu.1-driven macrophage differentiation and in primary cells. Runx1 deficiency decreased Pu.1-mediated activation of Mcsfr and Gmcsfr, accompanied by decreased histone acetylation at the Mcsfr and Gmcsfr promoters, and increased endogenous corepressor (Eto2, Sin3A, and Hdac2) coimmunoprecipitation with Pu.1. In cotransfection experiments, corepressors were excluded from a multiprotein complex containing full-length RUNX1 and PU.1. However, corepressors interacted with PU.1 if wild-type RUNX1 was replaced with truncated variants associated with leukemia. Histone deacetylase (HDAC) enzyme activity is a major component of corepressor function. HDAC inhibition using suberoylanilide hydroxamic acid or MS-275 significantly increased MCSFR and GMCSFR expression in leukemia cell lines that express PU.1 and mutated or translocated RUNX1. RUNX1 deficiency is associated with persistent corepressor interaction with PU.1. Thus, inhibiting HDAC can partly compensate for the functional consequences of RUNX1 deficiency.


Asunto(s)
Proteínas Co-Represoras/metabolismo , Subunidad alfa 2 del Factor de Unión al Sitio Principal/fisiología , Proteínas Proto-Oncogénicas/metabolismo , Transactivadores/metabolismo , Animales , Línea Celular Tumoral , Proteínas Co-Represoras/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Perfilación de la Expresión Génica , Regulación Leucémica de la Expresión Génica , Humanos , Ratones , Ratones Transgénicos , Análisis por Micromatrices , Células 3T3 NIH , Unión Proteica/genética , Proteínas Proto-Oncogénicas/genética , Transactivadores/genética , Transfección
15.
Opt Express ; 20(3): 2399-407, 2012 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-22330478

RESUMEN

We experimentally investigated the intensity cross-correlation between the upconverted photons and the unconverted photons in the single-photon frequency upconversion process with multi-longitudinal mode pump and signal sources. In theoretical analysis, with this multi-longitudinal mode of both signal and pump sources system, the properties of the signal photons could also be maintained as in the single-mode frequency upconversion system. Experimentally, based on the conversion efficiency of 80.5%, the joint probability of simultaneously detecting at upconverted and unconverted photons showed an anti-correlation as a function of conversion efficiency which indicated the upconverted photons were one-to-one from the signal photons. While due to the coherent state of the signal photons, the intensity cross-correlation function g(2)(0) was shown to be equal to unity at any conversion efficiency, agreeing with the theoretical prediction. This study will benefit the high-speed wavelength-tunable quantum state translation or photonic quantum interface together with the mature frequency tuning or longitudinal mode selection techniques.


Asunto(s)
Rayos Láser , Modelos Teóricos , Fotometría/métodos , Fotones , Simulación por Computador , Luz , Dispersión de Radiación , Estadística como Asunto
16.
Mol Cell Proteomics ; 9(6): 1031-46, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20177130

RESUMEN

A quantitative proteomics analysis of the macular Bruch membrane/choroid complex was pursued for insights into the molecular mechanisms of age-related macular degeneration (AMD). Protein in trephine samples from the macular region of 10 early/mid-stage dry AMD, six advanced dry AMD, eight wet AMD, and 25 normal control post-mortem eyes was analyzed by LC MS/MS iTRAQ (isobaric tags for relative and absolute quantitation) technology. A total of 901 proteins was quantified, including 556 proteins from > or =3 AMD samples. Most proteins differed little in amount between AMD and control samples and therefore reflect the proteome of normal macular tissues of average age 81. A total of 56 proteins were found to be elevated and 43 were found to be reduced in AMD tissues relative to controls. Analysis by category of disease progression revealed up to 16 proteins elevated or decreased in each category. About 60% of the elevated proteins are involved in immune response and host defense, including many complement proteins and damage-associated molecular pattern proteins such as alpha-defensins 1-3, protein S100s, crystallins, histones, and galectin-3. Four retinoid processing proteins were elevated only in early/mid-stage AMD, supporting a role for retinoids in AMD initiation. Proteins uniquely decreased in early/mid-stage AMD implicate hematologic malfunctions and weakened extracellular matrix integrity and cellular interactions. Galectin-3, a receptor for advanced glycation end products, was the most significantly elevated protein in advanced dry AMD, supporting a role for advanced glycation end products in dry AMD progression. The results endorse inflammatory processes in both early and advanced AMD pathology, implicate different pathways of progression to advanced dry and wet AMD, and provide a new database for hypothesis-driven and discovery-based studies of AMD.


Asunto(s)
Lámina Basal de la Coroides/metabolismo , Lámina Basal de la Coroides/patología , Proteínas del Ojo/metabolismo , Degeneración Macular/metabolismo , Degeneración Macular/patología , Proteómica/métodos , Anciano , Anciano de 80 o más Años , Western Blotting , Lámina Basal de la Coroides/citología , Progresión de la Enfermedad , Femenino , Humanos , Degeneración Macular/clasificación , Masculino , Proteoma/metabolismo
17.
Opt Express ; 19(14): 13497-502, 2011 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-21747504

RESUMEN

We demonstrated a laser ranging system with single photon detection at 1550 nm. The single-photon detector was a 1-GHz sine-wave gated InGaAs/InP avalanche photodiode. In daylight, 8-cm depth resolution was achieved directly by using a time-of-flight approach based on time-correlated single photon counting measurement. This system presented a potential for low energy level and eye-safe laser ranging system in long-range measurement.


Asunto(s)
Rayos Láser , Fotometría/instrumentación , Radar , Procesamiento de Señales Asistido por Computador/instrumentación , Diseño de Equipo , Análisis de Falla de Equipo
18.
Opt Lett ; 36(9): 1722-4, 2011 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-21540981

RESUMEN

We demonstrate photon-number-resolving detection based on coincidence frequency upconversion. Pumped by synchronized pulses, the photon signal of the coherent state at 1.04 µm was upconverted into visible replicas with preserved photon number distribution. The upconverted photons were then registered by a silicon multipixel photon counter. The photon-number-resolving performance was improved by reducing the background counts with a synchronous pump as the coincidence gate and reducing the intrinsic parametric fluorescence influence with long-wavelength pumping. A total detection efficiency of 3.7% was achieved with a quite low noise probability per pulse of 0.0002.

19.
Mol Cell Proteomics ; 8(8): 1921-33, 2009 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-19435712

RESUMEN

Age-related macular degeneration (AMD) causes severe vision loss in the elderly; early identification of AMD risk could help slow or prevent disease progression. Toward the discovery of AMD biomarkers, we quantified plasma protein N(epsilon)-carboxymethyllysine (CML) and pentosidine from 58 AMD and 32 control donors. CML and pentosidine are advanced glycation end products that are abundant in Bruch membrane, the extracellular matrix separating the retinal pigment epithelium from the blood-bearing choriocapillaris. We measured CML and pentosidine by LC-MS/MS and LC-fluorometry, respectively, and found higher mean levels of CML (approximately 54%) and pentosidine (approximately 64%) in AMD (p < 0.0001) relative to normal controls. Plasma protein fructosyl-lysine, a marker of early glycation, was found by amino acid analysis to be in equal amounts in control and non-diabetic AMD donors, supporting an association between AMD and increased levels of CML and pentosidine independent of other diseases like diabetes. Carboxyethylpyrrole (CEP), an oxidative modification from docosahexaenoate-containing lipids and also abundant in AMD Bruch membrane, was elevated approximately 86% in the AMD cohort, but autoantibody titers to CEP, CML, and pentosidine were not significantly increased. Compellingly higher mean levels of CML and pentosidine were present in AMD plasma protein over a broad age range. Receiver operating curves indicate that CML, CEP adducts, and pentosidine alone discriminated between AMD and control subjects with 78, 79, and 88% accuracy, respectively, whereas CML in combination with pentosidine provided approximately 89% accuracy, and CEP plus pentosidine provided approximately 92% accuracy. Pentosidine levels appeared slightly altered in AMD patients with hypertension and cardiovascular disease, indicating further studies are warranted. Overall this study supports the potential utility of plasma protein CML and pentosidine as biomarkers for assessing AMD risk and susceptibility, particularly in combination with CEP adducts and with concurrent analyses of fructosyl-lysine to detect confounding factors.


Asunto(s)
Arginina/análogos & derivados , Biomarcadores/sangre , Lisina/análogos & derivados , Degeneración Macular/sangre , Anciano , Anciano de 80 o más Años , Arginina/sangre , Autoanticuerpos/sangre , Proteínas Sanguíneas/metabolismo , Estudios de Casos y Controles , Cromatografía Liquida , Femenino , Fluorometría , Humanos , Modelos Logísticos , Lisina/sangre , Degeneración Macular/diagnóstico , Masculino , Espectrometría de Masas , Persona de Mediana Edad , Pirroles/química , Pirroles/inmunología
20.
Mol Cell Proteomics ; 8(6): 1338-49, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19202148

RESUMEN

Age-related macular degeneration (AMD) is a progressive disease and major cause of severe visual loss. Toward the discovery of tools for early identification of AMD susceptibility, we evaluated the combined predictive capability of proteomic and genomic AMD biomarkers. We quantified plasma carboxyethylpyrrole (CEP) oxidative protein modifications and CEP autoantibodies by ELISA in 916 AMD and 488 control donors. CEP adducts are uniquely generated from oxidation of docosahexaenoate-containing lipids that are abundant in the retina. Mean CEP adduct and autoantibody levels were found to be elevated in AMD plasma by approximately 60 and approximately 30%, respectively. The odds ratio for both CEP markers elevated was 3-fold greater or more in AMD than in control patients. Genotyping was performed for AMD risk polymorphisms associated with age-related maculopathy susceptibility 2 (ARMS2), high temperature requirement factor A1 (HTRA1), complement factor H, and complement C3, and the risk of AMD was predicted based on genotype alone or in combination with the CEP markers. The AMD risk predicted for those exhibiting elevated CEP markers and risk genotypes was 2-3-fold greater than the risk based on genotype alone. AMD donors carrying the ARMS2 and HTRA1 risk alleles were the most likely to exhibit elevated CEP markers. The results compellingly demonstrate higher mean CEP marker levels in AMD plasma over a broad age range. Receiver operating characteristic curves suggest that CEP markers alone can discriminate between AMD and control plasma donors with approximately 76% accuracy and in combination with genomic markers provide up to approximately 80% discrimination accuracy. Plasma CEP marker levels were altered slightly by several demographic and health factors that warrant further study. We conclude that CEP plasma biomarkers, particularly in combination with genomic markers, offer a potential early warning system for assessing susceptibility to this blinding, multifactorial disease.


Asunto(s)
Biomarcadores/metabolismo , Susceptibilidad a Enfermedades , Genoma , Degeneración Macular/metabolismo , Proteoma , Envejecimiento , Autoanticuerpos/sangre , Autoanticuerpos/metabolismo , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Serina Peptidasa A1 que Requiere Temperaturas Altas , Humanos , Degeneración Macular/genética , Degeneración Macular/inmunología , Polimorfismo Genético , Proteínas/genética , Serina Endopeptidasas/genética
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA