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1.
Cell ; 150(6): 1121-34, 2012 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-22980976

RESUMO

We report the results of whole-genome and transcriptome sequencing of tumor and adjacent normal tissue samples from 17 patients with non-small cell lung carcinoma (NSCLC). We identified 3,726 point mutations and more than 90 indels in the coding sequence, with an average mutation frequency more than 10-fold higher in smokers than in never-smokers. Novel alterations in genes involved in chromatin modification and DNA repair pathways were identified, along with DACH1, CFTR, RELN, ABCB5, and HGF. Deep digital sequencing revealed diverse clonality patterns in both never-smokers and smokers. All validated EFGR and KRAS mutations were present in the founder clones, suggesting possible roles in cancer initiation. Analysis revealed 14 fusions, including ROS1 and ALK, as well as novel metabolic enzymes. Cell-cycle and JAK-STAT pathways are significantly altered in lung cancer, along with perturbations in 54 genes that are potentially targetable with currently available drugs.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Fumar/genética , Fumar/patologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Aberrações Cromossômicas , Feminino , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação INDEL , Neoplasias Pulmonares/terapia , Masculino , Terapia de Alvo Molecular , Mutação Puntual , Proteína Reelina
2.
Cell ; 150(2): 264-78, 2012 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-22817890

RESUMO

Most mutations in cancer genomes are thought to be acquired after the initiating event, which may cause genomic instability and drive clonal evolution. However, for acute myeloid leukemia (AML), normal karyotypes are common, and genomic instability is unusual. To better understand clonal evolution in AML, we sequenced the genomes of M3-AML samples with a known initiating event (PML-RARA) versus the genomes of normal karyotype M1-AML samples and the exomes of hematopoietic stem/progenitor cells (HSPCs) from healthy people. Collectively, the data suggest that most of the mutations found in AML genomes are actually random events that occurred in HSPCs before they acquired the initiating mutation; the mutational history of that cell is "captured" as the clone expands. In many cases, only one or two additional, cooperating mutations are needed to generate the malignant founding clone. Cells from the founding clone can acquire additional cooperating mutations, yielding subclones that can contribute to disease progression and/or relapse.


Assuntos
Evolução Clonal , Leucemia Mieloide Aguda/genética , Mutação , Adulto , Idoso , Análise Mutacional de DNA , Progressão da Doença , Feminino , Estudo de Associação Genômica Ampla , Células-Tronco Hematopoéticas/metabolismo , Humanos , Leucemia Mieloide Aguda/fisiopatologia , Masculino , Pessoa de Meia-Idade , Proteínas de Fusão Oncogênica/genética , Recidiva , Pele/metabolismo , Adulto Jovem
3.
Int J Mol Sci ; 22(11)2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34072234

RESUMO

A silica-bound C-butylpyrogallol[4]arene chromatographic stationary phase was prepared and characterised by thermogravimetric analysis, scanning electron microscopy, NMR and mass spectrometry. The chromatographic performance was investigated by using C60 and C70 fullerenes in reverse phase mode via flash column and high-pressure liquid chromatography (HPLC). The resulting new stationary phase was observed to demonstrate size-selective molecular recognition as postulated from our in-silico studies. The silica-bound C-butylpyrogallol[4]arene flash and HPLC stationary phases were able to separate a C60- and C70-fullerene mixture more effectively than an RP-C18 stationary phase. The presence of toluene in the mobile phase plays a significant role in achieving symmetrical peaks in flash column chromatography.


Assuntos
Cromatografia em Gel/métodos , Cromatografia Líquida de Alta Pressão/métodos , Fulerenos/química , Fulerenos/isolamento & purificação , Técnicas de Química Sintética , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Teoria Quântica , Dióxido de Silício/química , Termogravimetria
4.
Angew Chem Int Ed Engl ; 60(44): 23878-23884, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34464506

RESUMO

A combination of charge density studies and solid state nuclear magnetic resonance (NMR) 1 JNC coupling measurements supported by periodic density functional theory (DFT) calculations is used to characterise the transition from an n-π* interaction to bond formation between a nucleophilic nitrogen atom and an electrophilic sp2 carbon atom in a series of crystalline peri-substituted naphthalenes. As the N⋅⋅⋅C distance reduces there is a sharp decrease in the Laplacian derived from increasing charge density between the two groups at ca. N⋅⋅⋅C = 1.8 Å, with the periodic DFT calculations predicting, and heteronuclear spin-echo NMR measurements confirming, the 1 JNC couplings of ≈3-6 Hz for long C-N bonds (1.60-1.65 Å), and 1 JNC couplings of <1 Hz for N⋅⋅⋅C >2.1 Å.

5.
Phys Chem Chem Phys ; 22(6): 3400-3413, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31984388

RESUMO

A combined multinuclear solid state NMR and gauge included projected augmented wave, density functional theory (GIPAW DFT) computational approach is evaluated to determine the four heteronuclear 1J(13C,17O) couplings in solid 17O enriched naphthalaldehydic acid. Direct multi-field 17O magic angle spinning (MAS), triple quantum MAS (3QMAS) and double rotation (DOR) experiments are initially utilised to evaluate the accuracy of the DFT approximations used in the calculation of the isotropic chemical shifts (δiso), quadrupole coupling constants (CQ) and asymmetry (ηQ) parameters. These combined approaches give δiso values of 313, 200 and 66 ppm for the carbonyl (C[double bond, length as m-dash]O), ether (-O-) and hydroxyl (-OH) environments, respectively, with the corresponding measured quadrupole products (PQ) being 8.2, 9.0 and 10.6 MHz. The geometry optimised DFT structure derived using the CASTEP code gives firm agreement with the shifts observed for the ether (δiso = 223, PQ = 9.4 MHz) and hydroxyl (δiso = 62, PQ = 10.5 MHz) environments but the unoptimised experimental XRD structure has better agreement for the carbonyl group (δiso = 320, PQ = 8.3 MHz). The determined δiso and ηQ values are shown to be consistent with bond lengths closer to 1.222 Å (experimental length) rather than the geometry optimised length of 1.238 Å. The geometry optimised DFT 1J(13C,17O) coupling to the hydroxyl is calculated as 20 Hz and the couplings to the ether were calculated to be 37 (O-C[double bond, length as m-dash]O) and 32 (O-C-OH) Hz. The scalar coupling parameters for the unoptimised experimental carbonyl group predict a 1J(13C,17O) value of 28 Hz, whilst optimisation gives a value of 27 Hz. These calculated 1J(13C,17O) couplings, together with estimations of the probability of each O environment being isotopically labelled (determined by electrospray ionisation mass spectrometry) and the measured refocussable transverse dephasing (T2') behaviour, are combined to simulate the experimental decay behaviour. Good agreement between the measured and calculated decay behaviour is observed.

6.
Nature ; 481(7382): 506-10, 2012 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-22237025

RESUMO

Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level. To determine the mutational spectrum associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC, SMC3, DIS3, DDX41 and DAXX) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.


Assuntos
Evolução Clonal/genética , Genoma Humano/genética , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Células Clonais/efeitos dos fármacos , Células Clonais/metabolismo , Células Clonais/patologia , Dano ao DNA/efeitos dos fármacos , Análise Mutacional de DNA , Genes Neoplásicos/genética , Genoma Humano/efeitos dos fármacos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Mutagênese/efeitos dos fármacos , Mutagênese/genética , Recidiva , Reprodutibilidade dos Testes
7.
Nature ; 486(7403): 353-60, 2012 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-22722193

RESUMO

To correlate the variable clinical features of oestrogen-receptor-positive breast cancer with somatic alterations, we studied pretreatment tumour biopsies accrued from patients in two studies of neoadjuvant aromatase inhibitor therapy by massively parallel sequencing and analysis. Eighteen significantly mutated genes were identified, including five genes (RUNX1, CBFB, MYH9, MLL3 and SF3B1) previously linked to haematopoietic disorders. Mutant MAP3K1 was associated with luminal A status, low-grade histology and low proliferation rates, whereas mutant TP53 was associated with the opposite pattern. Moreover, mutant GATA3 correlated with suppression of proliferation upon aromatase inhibitor treatment. Pathway analysis demonstrated that mutations in MAP2K4, a MAP3K1 substrate, produced similar perturbations as MAP3K1 loss. Distinct phenotypes in oestrogen-receptor-positive breast cancer are associated with specific patterns of somatic mutations that map into cellular pathways linked to tumour biology, but most recurrent mutations are relatively infrequent. Prospective clinical trials based on these findings will require comprehensive genome sequencing.


Assuntos
Inibidores da Aromatase/uso terapêutico , Aromatase/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Genoma Humano/genética , Anastrozol , Androstadienos/farmacologia , Androstadienos/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Reparo do DNA , Exoma/genética , Éxons/genética , Feminino , Variação Genética/genética , Humanos , Letrozol , MAP Quinase Quinase 4/genética , MAP Quinase Quinase Quinase 1/genética , Mutação/genética , Nitrilas/farmacologia , Nitrilas/uso terapêutico , Receptores de Estrogênio/metabolismo , Resultado do Tratamento , Triazóis/farmacologia , Triazóis/uso terapêutico
8.
Genome Res ; 24(2): 310-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24307552

RESUMO

Recent progress in next-generation sequencing has greatly facilitated our study of genomic structural variation. Unlike single nucleotide variants and small indels, many structural variants have not been completely characterized at nucleotide resolution. Deriving the complete sequences underlying such breakpoints is crucial for not only accurate discovery, but also for the functional characterization of altered alleles. However, our current ability to determine such breakpoint sequences is limited because of challenges in aligning and assembling short reads. To address this issue, we developed a targeted iterative graph routing assembler, TIGRA, which implements a set of novel data analysis routines to achieve effective breakpoint assembly from next-generation sequencing data. In our assessment using data from the 1000 Genomes Project, TIGRA was able to accurately assemble the majority of deletion and mobile element insertion breakpoints, with a substantively better success rate and accuracy than other algorithms. TIGRA has been applied in the 1000 Genomes Project and other projects and is freely available for academic use.


Assuntos
Componentes Genômicos , Variação Estrutural do Genoma , Projeto Genoma Humano , Software , Algoritmos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Análise de Sequência de DNA
9.
Nat Genet ; 40(9): 1076-83, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19165922

RESUMO

Using comparative sequencing approaches, we investigated the evolutionary history of the European-enriched 17q21.31 MAPT inversion polymorphism. We present a detailed, BAC-based sequence assembly of the inverted human H2 haplotype and compare it to the sequence structure and genetic variation of the corresponding 1.5-Mb region for the noninverted H1 human haplotype and that of chimpanzee and orangutan. We found that inversion of the MAPT region is similarly polymorphic in other great ape species, and we present evidence that the inversions occurred independently in chimpanzees and humans. In humans, the inversion breakpoints correspond to core duplications with the LRRC37 gene family. Our analysis favors the H2 configuration and sequence haplotype as the likely great ape and human ancestral state, with inversion recurrences during primate evolution. We show that the H2 architecture has evolved more extensive sequence homology, perhaps explaining its tendency to undergo microdeletion associated with mental retardation in European populations.


Assuntos
Inversão Cromossômica , Cromossomos Humanos Par 17 , Evolução Molecular , Polimorfismo Genético , Proteínas tau/genética , Animais , Sequência de Bases , Duplicação Gênica , Humanos , Modelos Biológicos , Dados de Sequência Molecular , Pan troglodytes/genética , Filogenia , Pongo pygmaeus/genética , Análise de Sequência de DNA
10.
N Engl J Med ; 368(22): 2059-74, 2013 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-23634996

RESUMO

BACKGROUND: Many mutations that contribute to the pathogenesis of acute myeloid leukemia (AML) are undefined. The relationships between patterns of mutations and epigenetic phenotypes are not yet clear. METHODS: We analyzed the genomes of 200 clinically annotated adult cases of de novo AML, using either whole-genome sequencing (50 cases) or whole-exome sequencing (150 cases), along with RNA and microRNA sequencing and DNA-methylation analysis. RESULTS: AML genomes have fewer mutations than most other adult cancers, with an average of only 13 mutations found in genes. Of these, an average of 5 are in genes that are recurrently mutated in AML. A total of 23 genes were significantly mutated, and another 237 were mutated in two or more samples. Nearly all samples had at least 1 nonsynonymous mutation in one of nine categories of genes that are almost certainly relevant for pathogenesis, including transcription-factor fusions (18% of cases), the gene encoding nucleophosmin (NPM1) (27%), tumor-suppressor genes (16%), DNA-methylation-related genes (44%), signaling genes (59%), chromatin-modifying genes (30%), myeloid transcription-factor genes (22%), cohesin-complex genes (13%), and spliceosome-complex genes (14%). Patterns of cooperation and mutual exclusivity suggested strong biologic relationships among several of the genes and categories. CONCLUSIONS: We identified at least one potential driver mutation in nearly all AML samples and found that a complex interplay of genetic events contributes to AML pathogenesis in individual patients. The databases from this study are widely available to serve as a foundation for further investigations of AML pathogenesis, classification, and risk stratification. (Funded by the National Institutes of Health.).


Assuntos
Leucemia Mieloide Aguda/genética , Mutação , Adulto , Ilhas de CpG , Metilação de DNA , Epigenômica , Feminino , Expressão Gênica , Fusão Gênica , Genoma Humano , Humanos , Leucemia Mieloide Aguda/classificação , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Nucleofosmina , Análise de Sequência de DNA/métodos
11.
Genome Res ; 23(3): 431-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23222849

RESUMO

Low-grade brain tumors (pilocytic astrocytomas) arising in the neurofibromatosis type 1 (NF1) inherited cancer predisposition syndrome are hypothesized to result from a combination of germline and acquired somatic NF1 tumor suppressor gene mutations. However, genetically engineered mice (GEM) in which mono-allelic germline Nf1 gene loss is coupled with bi-allelic somatic (glial progenitor cell) Nf1 gene inactivation develop brain tumors that do not fully recapitulate the neuropathological features of the human condition. These observations raise the intriguing possibility that, while loss of neurofibromin function is necessary for NF1-associated low-grade astrocytoma development, additional genetic changes may be required for full penetrance of the human brain tumor phenotype. To identify these potential cooperating genetic mutations, we performed whole-genome sequencing (WGS) analysis of three NF1-associated pilocytic astrocytoma (PA) tumors. We found that the mechanism of somatic NF1 loss was different in each tumor (frameshift mutation, loss of heterozygosity, and methylation). In addition, tumor purity analysis revealed that these tumors had a high proportion of stromal cells, such that only 50%-60% of cells in the tumor mass exhibited somatic NF1 loss. Importantly, we identified no additional recurrent pathogenic somatic mutations, supporting a model in which neuroglial progenitor cell NF1 loss is likely sufficient for PA formation in cooperation with a proper stromal environment.


Assuntos
Astrocitoma/diagnóstico , Astrocitoma/genética , Genes da Neurofibromatose 1 , Neurofibromina 1/genética , Adolescente , Alelos , Astrocitoma/patologia , Criança , Variações do Número de Cópias de DNA , Metilação de DNA , Feminino , Estudo de Associação Genômica Ampla , Humanos , Perda de Heterozigosidade , Masculino , Mutação , Neurofibromina 1/metabolismo , Fenótipo , Reprodutibilidade dos Testes , Alinhamento de Sequência , Análise de Sequência de DNA , Adulto Jovem
12.
Inorg Chem ; 55(17): 8543-51, 2016 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-27517741

RESUMO

Molecules of tris(2,2'-bipyridine-4-thiomethyl-BEDT-TTF)iron(II) (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) assemble in pairs to form a novel supramolecular capsular structure in the solid state. Three BEDT-TTF residues from one complex lie in the three grooves between coordinated bipyridines of the other complex, and vice versa, to form a capsule with 3-fold rotational symmetry and an internal volume of ca. 160 Å(3). Further aspects of the coordination chemistry of this ligand, its 6-substituted isomer, and the 2,2':6'2″-terpyridyl-4'-thiomethyl-BEDT-TTF analogue are described.

13.
Nature ; 464(7291): 999-1005, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20393555

RESUMO

Massively parallel DNA sequencing technologies provide an unprecedented ability to screen entire genomes for genetic changes associated with tumour progression. Here we describe the genomic analyses of four DNA samples from an African-American patient with basal-like breast cancer: peripheral blood, the primary tumour, a brain metastasis and a xenograft derived from the primary tumour. The metastasis contained two de novo mutations and a large deletion not present in the primary tumour, and was significantly enriched for 20 shared mutations. The xenograft retained all primary tumour mutations and displayed a mutation enrichment pattern that resembled the metastasis. Two overlapping large deletions, encompassing CTNNA1, were present in all three tumour samples. The differential mutation frequencies and structural variation patterns in metastasis and xenograft compared with the primary tumour indicate that secondary tumours may arise from a minority of cells within the primary tumour.


Assuntos
Neoplasias Encefálicas/genética , Neoplasias Encefálicas/secundário , Neoplasias da Mama/genética , Genoma Humano/genética , Mutação/genética , Transplante de Neoplasias , Adulto , Neoplasias da Mama/patologia , Variações do Número de Cópias de DNA/genética , Análise Mutacional de DNA , Progressão da Doença , Feminino , Frequência do Gene/genética , Genômica , Humanos , Translocação Genética/genética , Transplante Heterólogo , alfa Catenina/genética
14.
Beilstein J Org Chem ; 11: 1561-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26664576

RESUMO

Chiral molecular crystals built up by chiral molecules without inversion centers have attracted much interest owing to their versatile functionalities related to optical, magnetic, and electrical properties. However, there is a difficulty in chiral crystal growth due to the lack of symmetry. Therefore, we made the molecular design to introduce intermolecular hydrogen bonds in chiral crystals. Racemic and enantiopure bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives possessing hydroxymethyl groups as the source of hydrogen bonds were designed. The novel racemic trans-vic-(hydroxymethyl)(methyl)-BEDT-TTF 1, and racemic and enantiopure trans-vic-bis(hydroxymethyl)-BEDT-TTF 2 were synthesized. Moreover, the preparations, crystal structure analyses, and electrical resistivity measurements of the novel achiral charge transfer salt θ(21)-[(S,S)-2]3[(R,R)-2]3(ClO4)2 and the chiral salt α'-[(R,R)-2]ClO4(H2O) were carried out. In the former θ(21)-[(S,S)-2]3[(R,R)-2]3(ClO4)2, there are two sets of three crystallographically independent donor molecules [(S,S)-2]2[(R,R)-2] in a unit cell, where the two sets are related by an inversion center. The latter α'-[(R,R)-2]ClO4(H2O) is the chiral salt with included solvent H2O, which is not isostructural with the reported chiral salt α'-[(S,S)-2]ClO4 without H2O, but has a similar donor arrangement. According to the molecular design by introduction of hydroxy groups and a ClO4 (-) anion, many intermediate-strength intermolecular hydrogen bonds (2.6-3.0 Å) were observed in these crystals between electron donor molecules, anions, and included H2O solvent, which improve the crystallinity and facilitate the extraction of physical properties. Both salts are semiconductors with relatively low resistivities at room temperature and activation energies of 1.2 ohm cm with E a = 86 meV for θ(21)-[(S,S)-2]3[(R,R)-2]3(ClO4)2 and 0.6 ohm cm with E a = 140 meV for α'-[(R,R)-2]2ClO4(H2O), respectively. The variety of donor arrangements, θ(21) and two kinds of α'-types, and their electrical conductivities of charge transfer complexes based upon the racemic and enantiopure (S,S)-2, and (R,R)-2 donors originates not only from the chirality, but also the introduced intermolecular hydrogen bonds involving the hydroxymethyl groups, perchlorate anion, and the included solvent H2O.

15.
Nature ; 453(7192): 175-83, 2008 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-18464734

RESUMO

We present a draft genome sequence of the platypus, Ornithorhynchus anatinus. This monotreme exhibits a fascinating combination of reptilian and mammalian characters. For example, platypuses have a coat of fur adapted to an aquatic lifestyle; platypus females lactate, yet lay eggs; and males are equipped with venom similar to that of reptiles. Analysis of the first monotreme genome aligned these features with genetic innovations. We find that reptile and platypus venom proteins have been co-opted independently from the same gene families; milk protein genes are conserved despite platypuses laying eggs; and immune gene family expansions are directly related to platypus biology. Expansions of protein, non-protein-coding RNA and microRNA families, as well as repeat elements, are identified. Sequencing of this genome now provides a valuable resource for deep mammalian comparative analyses, as well as for monotreme biology and conservation.


Assuntos
Evolução Molecular , Genoma/genética , Ornitorrinco/genética , Animais , Composição de Bases , Dentição , Feminino , Impressão Genômica/genética , Humanos , Imunidade/genética , Masculino , Mamíferos/genética , MicroRNAs/genética , Proteínas do Leite/genética , Filogenia , Ornitorrinco/imunologia , Ornitorrinco/fisiologia , Receptores Odorantes/genética , Sequências Repetitivas de Ácido Nucleico/genética , Répteis/genética , Análise de Sequência de DNA , Espermatozoides/metabolismo , Peçonhas/genética , Zona Pelúcida/metabolismo
16.
RSC Adv ; 14(26): 18444-18452, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38860243

RESUMO

The family of radical-cation salts ß''-(BEDT-TTF)4[(A)M3+(C2O4)3]·guest (M = Fe, Cr, Ga, Al, Co, Mn, Rh, Ru; A = K+, H3O+, NH4 +) has produced superconductors, metals, semiconductors, and metal-insulators through introduction of different guest molecules into the structure. We present three new additions to the family ß''-(BEDT-TTF)4[(A)Cr(C2O4)3]·guest with the guest molecules toluene, phenol, or salicylaldehyde. These new guests are liquid or solid additives within the electrocrystallisation medium. All three salts show metallic behaviour from room temperature down to <10 K and do not show a superconducting transition.

17.
J Am Chem Soc ; 135(45): 17176-86, 2013 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-24147901

RESUMO

Enantiopure (S,S) and (R,R) dimethyl-ethylenedithio-tetrathiafulvalene (DM-EDT-TTF) 1 donors are synthesized by cross coupling followed by decarboxylation reactions. In the solid state the methyl groups are arranged in axial positions within sofa-type conformation for the six-membered rings. Crystalline radical cation salts formulated as [(S,S)-1]2PF6, [(R,R)-1]2PF6, and [(rac)-1]2PF6 are obtained by electrocrystallization. When the experiment is conducted with enantioenriched mixtures both enantiopure and racemic phases are obtained. The monoclinic enantiopure salts, containing four independent donors in the unit cell, show semiconducting behavior supported by band structure calculations of extended Hückel type. The racemic salt contains only one independent donor in the mixed valence oxidation state +0.5. Under ambient pressure the racemic material is metallic down to 120 K, while an applied pressure of 11.5 kbar completely suppresses the metal-insulator transition. Band structure calculations yield an open Fermi surface, typical for a pseudo-one-dimensional metal, with unperfected nesting, thus ruling out the possibility of charge or spin density modulations to be at the origin of the transition. Raman spectroscopy measurements, in agreement with structural analysis at 100 K, show no indication of low-temperature charge ordering in the racemic material at ambient pressure, thus suggesting Mott-type charge localization for the observed metal-insulator transition.

18.
Bioinformatics ; 28(14): 1923-4, 2012 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-22563071

RESUMO

UNLABELLED: Despite recent progress, computational tools that identify gene fusions from next-generation whole transcriptome sequencing data are often limited in accuracy and scalability. Here, we present a software package, BreakFusion that combines the strength of reference alignment followed by read-pair analysis and de novo assembly to achieve a good balance in sensitivity, specificity and computational efficiency. AVAILABILITY: http://bioinformatics.mdanderson.org/main/BreakFusion


Assuntos
Biologia Computacional/métodos , Análise de Sequência de RNA/métodos , Software , Transcriptoma , Linhagem Celular Tumoral , Humanos , Alinhamento de Sequência
19.
Chirality ; 25(8): 466-74, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23840032

RESUMO

The (S,S,S,S) and (R,R,R,R) enantiomers of tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) show equatorial conformation for the four methyl groups in the solid state, according to the single-crystal X-ray analyses. Theoretical calculations at the Density Functional Theory (DFT) and time-dependent (TD) DFT levels indicate higher gas phase stability for the axial conformer than the equatorial one by 1.25 kcal ∙ mole⁻¹ and allow the assignment of the UV-vis and circular dichroism transitions. A complete series of radical cation salts of 1:1 stoichiometry with the triiodide anion I3⁻ was obtained by electrocrystallization of both enantiopure and racemic forms of the donor. In the packing the donors are organized in dimers that further interact through S ∙ ∙ ∙ S intermolecular contacts and the triiodide anions lie parallel to pairs of oxidized donors. The conductivity of the racemate, which adopts the same, but disordered, structural type, is considerably lower, with much higher activation energy.

20.
Acta Crystallogr E Crystallogr Commun ; 79(Pt 1): 50-53, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36628361

RESUMO

In the crystal structure of the title compound, C22H26BN, the B atom acts to reduce the delocalization of the nitro-gen lone-pair electron density into the pyrrole ring, so that the two N-C bonds increase in length to 1.4005 (14) and 1.3981 (14) Å. The N-B bond length is 1.4425 (15) Å, which is longer than a typical N-B bond because the nitro-gen lone pair is not fully available to participate in the bond.

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