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1.
Hum Genomics ; 13(1): 41, 2019 08 30.
Article in English | MEDLINE | ID: mdl-31470908

ABSTRACT

BACKGROUND: Targeted therapies have greatly improved cancer patient prognosis. For instance, chronic myeloid leukemia is now well treated with imatinib, a tyrosine kinase inhibitor. Around 80% of the patients reach complete remission. However, despite its great efficiency, some patients are resistant to the drug. This heterogeneity in the response might be associated with pharmacokinetic parameters, varying between individuals because of genetic variants. To assess this issue, next-generation sequencing of large panels of genes can be performed from patient samples. However, the common problem in pharmacogenetic studies is the availability of samples, often limited. In the end, large sequencing data are obtained from small sample sizes; therefore, classical statistical analyses cannot be applied to identify interesting targets. To overcome this concern, here, we described original and underused statistical methods to analyze large sequencing data from a restricted number of samples. RESULTS: To evaluate the relevance of our method, 48 genes involved in pharmacokinetics were sequenced by next-generation sequencing from 24 chronic myeloid leukemia patients, either sensitive or resistant to imatinib treatment. Using a graphical representation, from 708 identified polymorphisms, a reduced list of 115 candidates was obtained. Then, by analyzing each gene and the distribution of variant alleles, several candidates were highlighted such as UGT1A9, PTPN22, and ERCC5. These genes were already associated with the transport, the metabolism, and even the sensitivity to imatinib in previous studies. CONCLUSIONS: These relevant tests are great alternatives to inferential statistics not applicable to next-generation sequencing experiments performed on small sample sizes. These approaches permit to reduce the number of targets and find good candidates for further treatment sensitivity studies.


Subject(s)
DNA-Binding Proteins/genetics , Endonucleases/genetics , Glucuronosyltransferase/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Nuclear Proteins/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 22/genetics , Transcription Factors/genetics , Adult , Aged , Aged, 80 and over , Alleles , Drug Resistance, Neoplasm/genetics , Female , Humans , Imatinib Mesylate/administration & dosage , Imatinib Mesylate/adverse effects , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Male , Middle Aged , Mutation/genetics , Pharmacogenomic Variants/genetics , Prognosis , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/adverse effects , Sample Size , UDP-Glucuronosyltransferase 1A9 , Young Adult
2.
J Hum Genet ; 61(8): 693-9, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27193221

ABSTRACT

Otopalatodigital spectrum disorders (OPDSD) constitute a group of dominant X-linked osteochondrodysplasias including four syndromes: otopalatodigital syndromes type 1 and type 2 (OPD1 and OPD2), frontometaphyseal dysplasia, and Melnick-Needles syndrome. These syndromes variably associate specific facial and extremities features, hearing loss, cleft palate, skeletal dysplasia and several malformations, and show important clinical overlap over the different entities. FLNA gain-of-function mutations were identified in these conditions. FLNA encodes filamin A, a scaffolding actin-binding protein. Here, we report phenotypic descriptions and molecular results of FLNA analysis in a large series of 27 probands hypothesized to be affected by OPDSD. We identified 11 different missense mutations in 15 unrelated probands (n=15/27, 56%), of which seven were novel, including one of unknown significance. Segregation analyses within families made possible investigating 20 additional relatives carrying a mutation. This series allows refining the phenotypic and mutational spectrum of FLNA mutations causing OPDSD, and providing suggestions to avoid the overdiagnosis of OPD1.


Subject(s)
Craniofacial Abnormalities/diagnosis , Craniofacial Abnormalities/genetics , Genetic Association Studies , Hand Deformities, Congenital/diagnosis , Hand Deformities, Congenital/genetics , Mutation , Osteochondrodysplasias/diagnosis , Osteochondrodysplasias/genetics , Phenotype , Alleles , Amino Acid Substitution , Exons , Facies , Female , Filamins/genetics , Humans , Male , Pedigree , Sequence Analysis, DNA
3.
Ann Neurol ; 78(6): 871-86, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26288984

ABSTRACT

OBJECTIVE: Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is caused by mutations in the SACS gene. SACS encodes sacsin, a protein whose function remains unknown, despite the description of numerous protein domains and the recent focus on its potential role in the regulation of mitochondrial physiology. This study aimed to identify new mutations in a large population of ataxic patients and to functionally analyze their cellular effects in the mitochondrial compartment. METHODS: A total of 321 index patients with spastic ataxia selected from the SPATAX network were analyzed by direct sequencing of the SACS gene, and 156 patients from the ATAXIC project presenting with congenital ataxia were investigated either by targeted or whole exome sequencing. For functional analyses, primary cultures of fibroblasts were obtained from 11 patients carrying either mono- or biallelic variants, including 1 case harboring a large deletion encompassing the entire SACS gene. RESULTS: We identified biallelic SACS variants in 33 patients from SPATAX, and in 5 nonprogressive ataxia patients from ATAXIC. Moreover, a drastic and recurrent alteration of the mitochondrial network was observed in 10 of the 11 patients tested. INTERPRETATION: Our results permit extension of the clinical and mutational spectrum of ARSACS patients. Moreover, we suggest that the observed mitochondrial network anomalies could be used as a trait biomarker for the diagnosis of ARSACS when SACS molecular results are difficult to interpret (ie, missense variants and heterozygous truncating variant). Based on our findings, we propose new diagnostic definitions for ARSACS using clinical, genetic, and cellular criteria.


Subject(s)
Biomarkers , Heat-Shock Proteins/physiology , Mitochondria , Muscle Spasticity/diagnosis , Spinocerebellar Ataxias/congenital , Adolescent , Adult , Cell Culture Techniques , Child , Cohort Studies , Female , Fibroblasts , Heat-Shock Proteins/genetics , Humans , Male , Middle Aged , Mitochondria/metabolism , Mitochondria/pathology , Mitochondria/physiology , Muscle Spasticity/genetics , Muscle Spasticity/pathology , Muscle Spasticity/physiopathology , Mutation , Spinocerebellar Ataxias/diagnosis , Spinocerebellar Ataxias/genetics , Spinocerebellar Ataxias/pathology , Spinocerebellar Ataxias/physiopathology , Young Adult
4.
Am J Pathol ; 184(8): 2174-84, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24909507

ABSTRACT

Neonatal thymectomy in BALB/c mice has been described as a model of gastric mucosa-associated lymphoid tissue (MALT) lymphoma (GML). By using this experimental system, we screened, for the first time to our knowledge, Helicobacter pylori GML-associated strains for their capacity to promote disease. A cohort of BALB/c mice underwent thymectomy at day 3 after birth (d3Tx). Successful thymic ablation was evaluated by the degree of lymphopenia in blood samples collected at 4 weeks of age. d3Tx and non-thymectomized controls were infected with either GML strains (B38 or B47) or control strains (SS1 or TN2GF4). Gastric samples collected at 6, 12, and 18 months after infection were studied for bacteria content, and submitted to histological, immunochemical, molecular, and immunological analyses. Severe gastric inflammation was only observed in d3Tx mice. In these animals, the gastric lamina propria was infiltrated with lymphoid cells organized in follicles composed of B cells with few infiltrating T cells. PCR of D/J IgH gene segments proved the monoclonality of infiltrating B cells, which strongly correlated with the presence of lymphoepithelial lesions. B-cell infiltrates were particularly prominent in mice infected with the B47-GML strain. No pathological changes were detected in noninfected d3Tx mice. We identified new H. pylori isolates adapted to the mouse stomach with high potential of GML development, which is only revealed in hosts rendered lymphopenic by neonatal thymic ablation.


Subject(s)
Disease Models, Animal , Gastric Mucosa/microbiology , Helicobacter pylori , Lymphoma, B-Cell, Marginal Zone/microbiology , Stomach Neoplasms/microbiology , Thymectomy , Animals , Animals, Newborn , Flow Cytometry , Immunohistochemistry , Lymphoma, B-Cell, Marginal Zone/immunology , Lymphoma, B-Cell, Marginal Zone/pathology , Mice , Mice, Inbred BALB C , Polymerase Chain Reaction , Stomach Neoplasms/immunology , Stomach Neoplasms/pathology
5.
Adv Mater ; 34(2): e2104054, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34648203

ABSTRACT

Passive plasmonic metasurfaces enable image multiplexing by displaying different images when altering the conditions of observation. Under white light, three-image multiplexing with polarization-selective switching has been recently demonstrated using femtosecond-laser-processed random plasmonic metasurfaces. Here, the implementation of image multiplexing is extended, thanks to a color-search algorithm, to various observation modes compatible with naked-eye observation under incoherent white light and to four-image multiplexing under polarized light. The laser-processed random plasmonic metasurfaces enabling image multiplexing exhibit self-organized patterns that can diffract light or induce dichroism through hybridization between the localized surface plasmon resonance of metallic nanoparticles and a lattice resonance. Improved spatial resolution makes the image quality compatible with commercial use in secured documents as well as the processing time and cost thanks to the use of a nanosecond laser. This high-speed and flexible laser process, based on energy-efficient nanoparticle reshaping and self-organization, produces centimeter-scale customized tamper-proof images at low cost, which can serve as overt security features.

6.
J Clin Invest ; 132(8)2022 04 15.
Article in English | MEDLINE | ID: mdl-35230976

ABSTRACT

Germline mutations that activate genes in the canonical RAS/MAPK signaling pathway are responsible for rare human developmental disorders known as RASopathies. Here, we analyzed the molecular determinants of Costello syndrome (CS) using a mouse model expressing HRAS p.G12S, patient skin fibroblasts, hiPSC-derived human cardiomyocytes, a HRAS p.G12V zebrafish model, and human fibroblasts expressing lentiviral constructs carrying HRAS p.G12S or HRAS p.G12A mutations. The findings revealed alteration of mitochondrial proteostasis and defective oxidative phosphorylation in the heart and skeletal muscle of CS mice that were also found in the cell models of the disease. The underpinning mechanisms involved the inhibition of the AMPK signaling pathway by mutant forms of HRAS, leading to alteration of mitochondrial proteostasis and bioenergetics. Pharmacological activation of mitochondrial bioenergetics and quality control restored organelle function in HRAS p.G12A and p.G12S cell models, reduced left ventricle hypertrophy in CS mice, and diminished the occurrence of developmental defects in the CS zebrafish model. Collectively, these findings highlight the importance of mitochondrial proteostasis and bioenergetics in the pathophysiology of RASopathies and suggest that patients with CS may benefit from treatment with mitochondrial modulators.


Subject(s)
Costello Syndrome , Germ-Line Mutation , Proto-Oncogene Proteins p21(ras) , AMP-Activated Protein Kinases/genetics , AMP-Activated Protein Kinases/metabolism , Animals , Costello Syndrome/genetics , Costello Syndrome/metabolism , Homeostasis , Humans , Mice , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Zebrafish/genetics , Zebrafish/metabolism
7.
Oncogene ; 39(3): 617-636, 2020 01.
Article in English | MEDLINE | ID: mdl-31527668

ABSTRACT

The basic understanding of the biological effects of eukaryotic translation initiation factors (EIFs) remains incomplete, notably for their roles independent of protein translation. Different EIFs exhibit nuclear localization and DNA-related functions have been proposed, but the understanding of EIFs novel functions beyond protein translation lacks of integrative analyses between the genomic and the proteomic levels. Here, the noncanonical function of EIF3F was studied in human lung adenocarcinoma by combining methods that revealed both the protein-protein and the protein-DNA interactions of this factor. We discovered that EIF3F promotes cell metastasis in vivo. The underpinning molecular mechanisms involved the regulation of a cluster of 34 metastasis-promoting genes including Snail2, as revealed by proteomics combined with immuno-affinity purification of EIF3F and ChIP-seq/Q-PCR analyses. The interaction between EIF3F and signal transducer and activator of transcription 3 (STAT3) controlled the EIF3F-mediated increase in Snail2 expression and cellular invasion, which were specifically abrogated using the STAT3 inhibitor Nifuroxazide or knockdown approaches. Furthermore, EIF3F overexpression reprogrammed energy metabolism through the activation of AMP-activated protein kinase and the stimulation of oxidative phosphorylation. Our findings demonstrate the role of EIF3F in the molecular control of cell migration, invasion, bioenergetics, and metastasis. The discovery of a role for EIF3F-STAT3 interaction in the genetic control of cell migration and metastasis in human lung adenocarcinoma could lead to the development of diagnosis and therapeutic strategies.


Subject(s)
Adenocarcinoma of Lung/genetics , Cell Nucleus/metabolism , Energy Metabolism/genetics , Eukaryotic Initiation Factor-3/metabolism , Gene Expression Regulation, Neoplastic , Lung Neoplasms/genetics , STAT3 Transcription Factor/metabolism , A549 Cells , Adenocarcinoma of Lung/metabolism , Adenocarcinoma of Lung/pathology , Animals , Cell Movement/drug effects , Cell Movement/genetics , Cell Nucleus/genetics , Cell Nucleus/pathology , Datasets as Topic , Energy Metabolism/drug effects , Eukaryotic Initiation Factor-3/genetics , Gene Knockdown Techniques , HeLa Cells , Humans , Hydroxybenzoates/pharmacology , Lung/cytology , Lung/pathology , Lung Neoplasms/metabolism , Lung Neoplasms/mortality , Lung Neoplasms/pathology , Male , Mice , Mutation , Neoplasm Invasiveness/genetics , Nitrofurans/pharmacology , Oxidative Phosphorylation/drug effects , RNA, Small Interfering/metabolism , RNA-Seq , STAT3 Transcription Factor/antagonists & inhibitors , STAT3 Transcription Factor/genetics , Snail Family Transcription Factors/genetics , Survival Analysis , Xenograft Model Antitumor Assays
8.
J Clin Med ; 8(5)2019 May 10.
Article in English | MEDLINE | ID: mdl-31083321

ABSTRACT

Cystic fibrosis (CF) is a systemic genetic disease that leads to pulmonary and digestive disorders. In the majority of CF patients, the intestine is the site of chronic inflammation and microbiota disturbances. The link between gut inflammation and microbiota dysbiosis is still poorly understood. The main objective of this study was to assess gut microbiota composition in CF children depending on their intestinal inflammation. We collected fecal samples from 20 children with CF. Fecal calprotectin levels were measured and fecal microbiota was analyzed by 16S rRNA sequencing. We observed intestinal inflammation was associated with microbiota disturbances characterized mainly by increased abundances of Staphylococcus, Streptococcus, and Veillonella dispar, along with decreased abundances of Bacteroides, Bifidobacterium adolescentis, and Faecalibacterium prausnitzii. Those changes exhibited similarities with that of Crohn's disease (CD), as evidenced by the elevated CD Microbial-Dysbiosis index that we applied for the first time in CF. Furthermore, the significant over-representation of Streptococcus in children with intestinal inflammation appears to be specific to CF and raises the issue of gut-lung axis involvement. Taken together, our results provide new arguments to link gut microbiota and intestinal inflammation in CF and suggest the key role of the gut-lung axis in the CF evolution.

9.
Sci Rep ; 8(1): 5446, 2018 04 03.
Article in English | MEDLINE | ID: mdl-29615661

ABSTRACT

Spondyloarthritis (SpA) pathophysiology remains largely unknown. While the association with genetic factors has been established for decades, the influence of gut microbiota is only an emerging direction of research. Despite the remarkable efficacy of anti-TNF-α treatments, non-responders are frequent and no predictive factors of patient outcome have been identified. Our objective was to investigate the modifications of intestinal microbiota composition in patients suffering from SpA three months after an anti-TNF-α treatment. We performed 16S rDNA sequencing of 38 stool samples from 19 spondyloarthritis patients before and three months after anti-TNF-α treatment onset. SpA activity was assessed at each time using ASDAS and BASDAI scores. Some modifications of the microbiota composition were observed after three months of anti-TNF-α treatment, but no specific taxon was modified, whatever the clinical response. We identified a particular taxonomic node before anti-TNF-α treatment that can predict the clinical response as a biomarker, with a higher proportion of Burkholderiales order in future responder patients. This study suggests a cross-influence between anti-TNF-α treatment and intestinal microbiota. If its results are confirmed on larger groups of patients, it may pave the way to the development of predictive tests suitable for clinical practices.


Subject(s)
Gastrointestinal Microbiome/drug effects , Spondylarthritis/drug therapy , Spondylarthritis/microbiology , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adult , Feces/microbiology , Female , Humans , Male , Treatment Outcome
10.
Eur J Hum Genet ; 15(8): 843-7, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17473832

ABSTRACT

The Rubinstein-Taybi syndrome (RTS) is a rare autosomal-dominant disease associated with 10-15% of cases with 16p13.3 microdeletions involving the CREB-binding protein gene (CREBBP). We used array-comparative genomic hybridization and Quantitative multiplex fluorescent-PCR (QMF-PCR) to search for dosage anomalies in the 16p13.3 region and the CREBBP gene. We first constructed a microarray covering 2 Mb that carries seven BAC and 34 cosmid clones, as well as 26 low-molecular-weight probes (1000-1500 bp) that are spread along the CREBBP gene. To increase further the resolution inside the CREBBP gene, we used QMF-PCR assays providing a 7 kb resolution. The deletions characterized in this work extended between as little as 3.3 kb and 6.5 Mb. Some deletions were restricted to just a few exons of CREBBP, some deleted either the 5' or the 3' end of the gene plus adjacent genomic segments, others deleted the whole gene away. We also identified a duplication of exon 16. We showed that CREBBP dosage anomalies constitute a common cause of RTS. CREBBP high-resolution gene dosage search is therefore highly recommended for RTS diagnosis. No correlation was found between the type of deletion and the patients' phenotype. All patients had typical RTS, and there was no particular severity associated with certain alterations.


Subject(s)
CREB-Binding Protein/genetics , Gene Dosage , Rubinstein-Taybi Syndrome/genetics , Sequence Deletion , Base Sequence , Humans
11.
Genome Announc ; 4(3)2016 Jun 16.
Article in English | MEDLINE | ID: mdl-27313300

ABSTRACT

Mycoplasma meleagridis and Mycoplasma gallinarum are bacteria that affect birds, but little is known about the genetic basis of their interaction with chickens and other poultry. Here, we sequenced the genomes of M. meleagridis strain MM_26B8_IPT and M. gallinarum strain Mgn_IPT, both isolated from chickens showing respiratory symptoms, poor growth, reduction in hatchability, and loss of production.

12.
PLoS One ; 11(2): e0148583, 2016.
Article in English | MEDLINE | ID: mdl-26910855

ABSTRACT

The rapid Arab-Islamic conquest during the early Middle Ages led to major political and cultural changes in the Mediterranean world. Although the early medieval Muslim presence in the Iberian Peninsula is now well documented, based in the evaluation of archeological and historical sources, the Muslim expansion in the area north of the Pyrenees has only been documented so far through textual sources or rare archaeological data. Our study provides the first archaeo-anthropological testimony of the Muslim establishment in South of France through the multidisciplinary analysis of three graves excavated at Nimes. First, we argue in favor of burials that followed Islamic rites and then note the presence of a community practicing Muslim traditions in Nimes. Second, the radiometric dates obtained from all three human skeletons (between the 7th and the 9th centuries AD) echo historical sources documenting an early Muslim presence in southern Gaul (i.e., the first half of 8th century AD). Finally, palaeogenomic analyses conducted on the human remains provide arguments in favor of a North African ancestry of the three individuals, at least considering the paternal lineages. Given all of these data, we propose that the skeletons from the Nimes burials belonged to Berbers integrated into the Umayyad army during the Arab expansion in North Africa. Our discovery not only discusses the first anthropological and genetic data concerning the Muslim occupation of the Visigothic territory of Septimania but also highlights the complexity of the relationship between the two communities during this period.


Subject(s)
Archaeology , Burial , Genomics , Islam , Paleontology , Ethnicity , France , Humans , Male
13.
Thromb Haemost ; 113(1): 66-76, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25374097

ABSTRACT

The Genetic Markers for Thrombosis (GMT) study compared the relative influence of ethnicity and thrombotic phenotype regarding the distribution of SNPs implicated in haemostasis pathophysiology ("haemostaseome"). We assessed 384 SNPs in three groups, each of 480 subjects: 1) general population of Aquitaine region (Southwestern France) used as control; 2) patients with venous thromboembolism from the same area; and 3) autochthonous Basques, a genetic isolate, who demonstrate unusual characteristics regarding the coagulation system. This study sought to evaluate i) the value of looking for a large number of genes in order to identify new genetic markers of thrombosis, ii) the value of investigating low risk factors and potential preferential associations, iii) the impact of ethnicity on the characterisation of markers for thrombosis. We did not detect any previously unrecognised SNP significantly associated with thrombosis risk or any preferential associations of low-risk factors in patients with thrombosis. The sum of Ï°² values for our 110 significant SNPs demonstrated a smaller genetic distance between patients and controls (321 cumulated Ï°² value) than between Basques and controls (1,570 cumulated Ï°² value). Hence, our study confirms the genetic particularity of Basques especially regarding a significantly lower expression of the non-O blood group (p< 0.0004). This is mitigated by a higher prevalence of factor II Leiden (p< 0.02) while factor V Leiden prevalence does not differ. Numerous other differences covering a wide range of proteins of the haemostaseome may result in an overall different genetic risk for venous thromboembolism.


Subject(s)
Ethnicity/genetics , Hemostasis/genetics , Polymorphism, Single Nucleotide , Venous Thromboembolism/ethnology , Venous Thromboembolism/genetics , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Chi-Square Distribution , Child , Child, Preschool , Factor V/genetics , Female , France/epidemiology , Gene Frequency , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Infant , Infant, Newborn , Male , Middle Aged , Mutation , Phenotype , Prothrombin/genetics , Risk Assessment , Risk Factors , Venous Thromboembolism/diagnosis , Young Adult
14.
J Clin Anesth ; 22(5): 334-9, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20650379

ABSTRACT

STUDY OBJECTIVE: To evaluate local anesthetic spread on the frequency of success of musculocutaneous nerve block, and to determine needle-to-target-nerve distance by ultrasound imaging and electrical stimulation. DESIGN: Observational study. SETTINGS: Private hospital. PATIENTS: 48 ASA physical status I and II adults (16 men and 32 women) scheduled for elective carpal tunnel release or wrist ganglion cyst surgery in an outpatient setting. INTERVENTIONS: The musculocutaneous nerve (MCN) was identified by ultrasound. An insulated needle connected to an electrical stimulator in the "off" position was inserted in the biceps side of the probe in the plane of the ultrasound beam. The needle tip was placed in the vicinity of the MCN. MEASUREMENTS: Local anesthetic spread pattern was determined by ultrasound imaging. The lowest effective current intensity was registered. The average depth of the MCN was measured by ultrasound. MAIN RESULTS: In all patients, the local anesthetic solution spread was uneven. In 32% of patients (15/47), motor response was still elicited with electrical stimulation intensity lower or equal to 0.3 mA. In 26% of patients (12/47), motor response disappeared with electrical stimulation intensity higher or equal to 0.6 mA. In 42% of patients (20/47), motor response disappeared at intensities between 0.3 mA and 0.5 mA. CONCLUSIONS: A high success rate of MCN anesthesia occurred with non-circumferential spread of local anesthetic solution. Electrical current intensity was not a reliable indicator of needle-to-target-nerve distance.


Subject(s)
Anesthetics, Local/pharmacology , Carpal Tunnel Syndrome/surgery , Ganglion Cysts/surgery , Nerve Block/methods , Adult , Aged , Anesthetics, Local/administration & dosage , Electric Stimulation/methods , Female , Humans , Male , Middle Aged , Musculocutaneous Nerve , Ultrasonography, Interventional/methods , Wrist
15.
Nano Lett ; 5(4): 615-9, 2005 Apr.
Article in English | MEDLINE | ID: mdl-15826096

ABSTRACT

The sub-diffraction imaging of the optical near-field in nanostructures, based on a photochemical technique, is reported. A photosensitive azobenzene-dye polymer is spin coated onto lithographic structures and is subsequently irradiated with laser light. Photoinduced mass transport creates topographic modifications at the polymer film surface that are then measured with atomic force microscopy (AFM). The AFM images correlate with rigorous theoretical calculations of the near-field intensities for a range of different nanostructures and illumination polarizations. This approach is a first step toward additional methods for resolving confined optical near fields, which can augment scanning probe methodologies for high spatial resolution of optical near fields.

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