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1.
Nucleic Acids Res ; 45(5): 2223-2241, 2017 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-28161714

RESUMO

Autoinhibition enables spatial and temporal regulation of cellular processes by coupling protein activity to surrounding conditions, often via protein partnerships or signaling pathways. We report the molecular basis of DNA-binding autoinhibition of ETS transcription factors ETV1, ETV4 and ETV5, which are often overexpressed in prostate cancer. Inhibitory elements that cooperate to repress DNA binding were identified in regions N- and C-terminal of the ETS domain. Crystal structures of these three factors revealed an α-helix in the C-terminal inhibitory domain that packs against the ETS domain and perturbs the conformation of its DNA-recognition helix. Nuclear magnetic resonance spectroscopy demonstrated that the N-terminal inhibitory domain (NID) is intrinsically disordered, yet utilizes transient intramolecular interactions with the DNA-recognition helix of the ETS domain to mediate autoinhibition. Acetylation of selected lysines within the NID activates DNA binding. This investigation revealed a distinctive mechanism for DNA-binding autoinhibition in the ETV1/4/5 subfamily involving a network of intramolecular interactions not present in other ETS factors. These distinguishing inhibitory elements provide a platform through which cellular triggers, such as protein-protein interactions or post-translational modifications, may specifically regulate the function of these oncogenic proteins.


Assuntos
Proteínas E1A de Adenovirus/química , Proteínas de Ligação a DNA/química , DNA/química , Proteínas Intrinsicamente Desordenadas/química , Processamento de Proteína Pós-Traducional , Proteínas Proto-Oncogênicas/química , Fatores de Transcrição/química , Acetilação , Proteínas E1A de Adenovirus/genética , Proteínas E1A de Adenovirus/metabolismo , Sítios de Ligação , Clonagem Molecular , Cristalografia por Raios X , DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Cinética , Lisina/química , Lisina/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-ets , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
2.
Nano Lett ; 16(2): 849-55, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26729449

RESUMO

By exploiting the very recent discovery of the piezoelectricity in odd-numbered layers of two-dimensional molybdenum disulfide (MoS2), we show the possibility of reversibly tuning the photoluminescence of single and odd-numbered multilayered MoS2 using high frequency sound wave coupling. We observe a strong quenching in the photoluminescence associated with the dissociation and spatial separation of electrons-holes quasi-particles at low applied acoustic powers. At the same applied powers, we note a relative preference for ionization of trions into excitons. This work also constitutes the first visual presentation of the surface displacement in one-layered MoS2 using laser Doppler vibrometry. Such observations are associated with the acoustically generated electric field arising from the piezoelectric nature of MoS2 for odd-numbered layers. At larger applied powers, the thermal effect dominates the behavior of the two-dimensional flakes. Altogether, the work reveals several key fundamentals governing acousto-optic properties of odd-layered MoS2 that can be implemented in future optical and electronic systems.

3.
Chem Asian J ; : e202400003, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39036883

RESUMO

The development of new thermoelectric conversion and cooling materials is an important means of addressing global climate and heat emissions in the future. While heavy and toxic elements like tellurium and lead are traditionally used to make thermoelectric materials with poor mechanical properties, recent decades have seen a gradual push towards greener and more sustainable alternatives. One such potential alternative material for thermoelectric and thermal management applications would be the Nitinol (TiNi) shape memory alloy, due to their superior mechanical properties. In this study, we have investigated the use of 3D melt printing techniques that can be used to achieve thermoelectric performance and efficiency of elastic memory alloys below 500 °C. The electrical and thermal properties of TiNiCu materials and their relation to morphology were investigated. All the alloys show similar effect sizes, their fatigue behavior is however different. By adjusting the composition of Ti and Ni elements and we have obtained memory alloys with high thermoelectric properties, with a 50% increase in power factor and a 100% increase in ZT values.

4.
Proc Natl Acad Sci U S A ; 107(22): 10026-31, 2010 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-20534573

RESUMO

Ras/MAPK signaling is often aberrantly activated in human cancers. The downstream effectors are transcription factors, including those encoded by the ETS gene family. Using cell-based assays and biophysical measurements, we have determined the mechanism by which Ras/MAPK signaling affects the function of Ets1 via phosphorylation of Thr38 and Ser41. These ERK2 phosphoacceptors lie within the unstructured N-terminal region of Ets1, immediately adjacent to the PNT domain. NMR spectroscopic analyses demonstrated that the PNT domain is a four-helix bundle (H2-H5), resembling the SAM domain, appended with two additional helices (H0-H1). Phosphorylation shifted a conformational equilibrium, displacing the dynamic helix H0 from the core bundle. The affinity of Ets1 for the TAZ1 (or CH1) domain of the coactivator CBP was enhanced 34-fold by phosphorylation, and this binding was sensitive to ionic strength. NMR-monitored titration experiments mapped the interaction surfaces of the TAZ1 domain and Ets1, the latter encompassing both the phosphoacceptors and PNT domain. Charge complementarity of these surfaces indicate that electrostatic forces act in concert with a conformational equilibrium to mediate phosphorylation effects. We conclude that the dynamic helical elements of Ets1, appended to a conserved structural core, constitute a phospho-switch that directs Ras/MAPK signaling to downstream changes in gene expression. This detailed structural and mechanistic information will guide strategies for targeting ETS proteins in human disease.


Assuntos
Proteína de Ligação a CREB/metabolismo , Proteína Proto-Oncogênica c-ets-1/metabolismo , Proteínas ras/metabolismo , Sequência de Aminoácidos , Animais , Proteína de Ligação a CREB/química , Sequência Conservada , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Modelos Moleculares , Simulação de Dinâmica Molecular , Dados de Sequência Molecular , Células NIH 3T3 , Ressonância Magnética Nuclear Biomolecular , Fosforilação , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteína Proto-Oncogênica c-ets-1/química , Proteína Proto-Oncogênica c-ets-1/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Eletricidade Estática
5.
J Biol Chem ; 286(22): 19816-29, 2011 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-21383010

RESUMO

DAXX is a scaffold protein with diverse roles that often depend upon binding SUMO via its N- and/or C-terminal SUMO-interacting motifs (SIM-N and SIM-C). Using NMR spectroscopy, we characterized the in vitro binding properties of peptide models of SIM-N and SIM-C to SUMO-1 and SUMO-2. In each case, binding was mediated by hydrophobic and electrostatic interactions and weakened with increasing ionic strength. Neither isolated SIM showed any significant paralog specificity, and the measured µM range K(D) values of SIM-N toward both SUMO-1 and SUMO-2 were ∼4-fold lower than those of SIM-C. Furthermore, SIM-N bound SUMO-1 predominantly in a parallel orientation, whereas SIM-C interconverted between parallel and antiparallel binding modes on an ms to µs time scale. The differences in affinities and binding modes are attributed to the differences in charged residues that flank the otherwise identical hydrophobic core sequences of the two SIMs. In addition, within its native context, SIM-N bound intramolecularly to the adjacent N-terminal helical bundle domain of DAXX, thus reducing its apparent affinity for SUMO. This behavior suggests a possible autoregulatory mechanism for DAXX. The interaction of a C-terminal fragment of DAXX with an N-terminal fragment of the sumoylated Ets1 transcription factor was mediated by SIM-C. Importantly, this interaction did not involve any direct contacts between DAXX and Ets1, but rather was derived from the non-covalent binding of SIM-C to SUMO-1, which in turn was covalently linked to the unstructured N-terminal segment of Ets1. These results provide insights into the binding mechanisms and hence biological roles of the DAXX SUMO-interacting motifs.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Transporte/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Nucleares/metabolismo , Dobramento de Proteína , Proteínas Adaptadoras de Transdução de Sinal/química , Proteínas Adaptadoras de Transdução de Sinal/genética , Motivos de Aminoácidos , Animais , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas Correpressoras , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Chaperonas Moleculares , Proteínas Nucleares/química , Proteínas Nucleares/genética , Estrutura Terciária de Proteína , Proteína Proto-Oncogênica c-ets-1/química , Proteína Proto-Oncogênica c-ets-1/genética , Proteína Proto-Oncogênica c-ets-1/metabolismo , Proteína SUMO-1/química , Proteína SUMO-1/genética , Proteína SUMO-1/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/química , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/genética , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação/fisiologia
6.
Nanoscale ; 13(33): 14110-14118, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477692

RESUMO

Detonation nanodiamonds (DNDs) are becoming increasingly important in science and technology with applications from drug delivery to tribology. DNDs are known to self-assemble into fractal-like aggregates in water, but their colloidal properties remain poorly understood. Here, the effect of salt and particle concentration on the size and shape of these aggregates is investigated using dynamic light scattering and small-angle X-ray scattering. Our results suggest the existence of two particle aggregate populations with diameters on the scale of 50 nm and 300 nm, respectively. The concentration of NaCl, in the range 0.005-1 mM, does not have a significant effect on the size or shape of the particle aggregates. The hydrodynamic radius of both aggregate populations decreases as the DND concentration increases from 0.01 to 2 mg mL-1. At the same time, the particle aggregates become denser and their overall shape changes from disk-like to rod-like with increasing DND concentration. We identify unexpected similarities between the aggregate structures observed for DNDs and those commonly observed for concentrated colloidal particles in high salt environments, described by classical colloid aggregation theories. Our results contribute to the fundamental understanding of the colloidal properties of DNDs and pave the way for the engineering of novel nanoparticle-based systems that make use of DNDs' unique colloidal properties for future applications.

7.
Biochim Biophys Acta ; 1784(7-8): 1087-97, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18472023

RESUMO

InterFeron-gamma Inducible protein 16 (IFI16) belongs to the interferon inducible HIN200 protein family that contains transcriptional regulators linked to cell cycle regulation and differentiation. All family members contain at most two domains of 200 amino acids, called HIN200, each containing two Oligonucleotide/Oligosaccharide Binding (OB) folds. IFI16 is involved in transcriptional repression and is a component of the DNA repair multi-protein complex known as BASC, which forms after UV-induced DNA damage. In this study, we used fold recognition and biophysical approaches as a tool to infer and validate functions to the HIN200 domain. Since the best template to model IFI16-HIN200 is Replication Protein A (RPA) in complex with single-stranded nucleic acids, we tested six RPA nucleic acid-binding characteristics for IFI16-HIN200. Our results indicate that IFI16-HIN200 is an RPA-like, OB-fold, nucleic acid-binding protein that binds to ssDNA with higher affinity than to dsDNA, recognizes ssDNA in the same orientation as RPA, oligomerizes upon ssDNA binding, wraps and stretches ssDNA, but does not destabilize dsDNA. We finally propose a framework model explaining how the HIN200 domain could prevent ssDNA from re-annealing.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Sequência de Bases , Biopolímeros/química , Biopolímeros/metabolismo , Clonagem Molecular , Primers do DNA , Transferência Ressonante de Energia de Fluorescência , Humanos , Mutagênese Sítio-Dirigida , Proteínas Nucleares/genética , Fosfoproteínas/genética , Ligação Proteica
8.
Sci Rep ; 8(1): 2478, 2018 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-29410508

RESUMO

Detonation nanodiamonds are of vital significance to many areas of science and technology. However, their fluorescence properties have rarely been explored for applications and remain poorly understood. We demonstrate significant fluorescence from the visible to near-infrared spectral regions from deaggregated, single-digit detonation nanodiamonds dispersed in water produced via post-synthesis oxidation. The excitation wavelength dependence of this fluorescence is analyzed in the spectral region from 400 nm to 700 nm as well as the particles' absorption characteristics. We report a strong pH dependence of the fluorescence and compare our results to the pH dependent fluorescence of aromatic hydrocarbons. Our results significantly contribute to the current understanding of the fluorescence of carbon-based nanomaterials in general and detonation nanodiamonds in particular.


Assuntos
Carbono/química , Nanodiamantes/química , Fluorescência , Humanos , Concentração de Íons de Hidrogênio , Nanomedicina/métodos , Oxirredução , Soluções , Espectrometria de Fluorescência/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Água/química
9.
ACS Appl Mater Interfaces ; 10(10): 8474-8484, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29470044

RESUMO

Additive manufacturing using selective laser melted titanium (SLM-Ti) is used to create bespoke items across many diverse fields such as medicine, defense, and aerospace. Despite great progress in orthopedic implant applications, such as for "just in time" implants, significant challenges remain with regards to material osseointegration and the susceptibility to bacterial colonization on the implant. Here, we show that polycrystalline diamond coatings on these titanium samples can enhance biological scaffold interaction improving medical implant applicability. The highly conformable coating exhibited excellent bonding to the substrate. Relative to uncoated SLM-Ti, the diamond coated samples showed enhanced mammalian cell growth, enriched apatite deposition, and reduced microbial S. aureus activity. These results open new opportunities for novel coatings on SLM-Ti devices in general and especially show promise for improved biomedical implants.


Assuntos
Titânio/química , Animais , Materiais Revestidos Biocompatíveis , Diamante , Teste de Materiais , Osseointegração , Staphylococcus aureus , Propriedades de Superfície
10.
Sci Rep ; 8(1): 1268, 2018 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-29352215

RESUMO

Traditional optical fibers are insensitive to magnetic fields, however many applications would benefit from fiber-based magnetometry devices. In this work, we demonstrate a magnetically sensitive optical fiber by doping nanodiamonds containing nitrogen vacancy centers into tellurite glass fibers. The fabrication process provides a robust and isolated sensing platform as the magnetic sensors are fixed in the tellurite glass matrix. Using optically detected magnetic resonance from the doped nanodiamonds, we demonstrate detection of local magnetic fields via side excitation and longitudinal collection. This is a first step towards intrinsically magneto-sensitive fiber devices with future applications in medical magneto-endoscopy and remote mineral exploration sensing.

11.
Nanoscale ; 9(38): 14690-14702, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28944813

RESUMO

Transparent non-volatile memory devices are desirable for realizing visually-clear integrated systems for information storage. Optical transparency provides advantages in applications such as smart glass electronic devices and wearable electronics. However, achieving high transparency limits the choice of active layers as well as the electrodes; thereby, constraining device processing and performance. Here, we demonstrate bilayer transparent memory cells using room temperature deposited amorphous strontium titanate as the functional material and indium tin oxide electrodes. The entire device is fabricated on glass, making the system highly transparent (>85%) in the visible spectrum. The devices exhibit switching ratios of over two orders of magnitude with measured retention of 105 s and endurance 104 cycles. Through the cross-sectional microstructural analyses it is shown that the asymmetric interfaces and distribution of oxygen vacancies in the bilayer oxide stack are responsible for defining the bipolar resistive switching behaviors. A photoluminescence mapping technique is employed to map the evolution of oxygen vacancies and pinpoint the location of the conductive filament. A transient response to optical excitation (using UV and blue light) is demonstrated in the high resistance state which indicates their potential as multifunctional memories for future transparent electronics.

12.
ACS Nano ; 11(11): 10924-10934, 2017 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-29088544

RESUMO

Detonation nanodiamonds (DNDs) have unique physical and chemical properties that make them invaluable in many applications. However, DNDs are generally assumed to show weak fluorescence, if any, unless chemically modified with organic molecules. We demonstrate that detonation nanodiamonds exhibit significant and excitation-wavelength-dependent fluorescence from the visible to the near-infrared spectral region above 800 nm, even without the engraftment of organic molecules to their surfaces. We show that this fluorescence depends on the surface functionality of the DND particles. The investigated functionalized DNDs, produced from the same purified DND as well as the as-received polyfunctional starting material, are hydrogen, hydroxyl, carboxyl, ethylenediamine, and octadecylamine-terminated. All DNDs are investigated in solution and on a silicon wafer substrate and compared to fluorescent high-pressure high-temperature nanodiamonds. The brightest fluorescence is observed from octadecylamine-functionalized particles and is more than 100 times brighter than the least fluorescent particles, carboxylated DNDs. The majority of photons emitted by all particle types likely originates from non-diamond carbon. However, we locally find bright and photostable fluorescence from nitrogen-vacancy centers in diamond in hydrogenated, hydroxylated, and carboxylated detonation nanodiamonds. Our results contribute to understanding the effects of surface chemistry on the fluorescence of DNDs and enable the exploration of the fluorescent properties of DNDs for applications in theranostics as nontoxic fluorescent labels, sensors, nanoscale tracers, and many others where chemically stable and brightly fluorescent nanoparticles with tailorable surface chemistry are needed.

13.
J Mol Biol ; 429(20): 2975-2995, 2017 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-28728983

RESUMO

The recruitment of transcriptional cofactors by sequence-specific transcription factors challenges the basis of high affinity and selective interactions. Extending previous studies that the N-terminal activation domain (AD) of ETV5 interacts with Mediator subunit 25 (MED25), we establish that similar, aromatic-rich motifs located both in the AD and in the DNA-binding domain (DBD) of the related ETS factor ETV4 interact with MED25. These ETV4 regions bind MED25 independently, display distinct kinetics, and combine to contribute to a high-affinity interaction of full-length ETV4 with MED25. High-affinity interactions with MED25 are specific for the ETV1/4/5 subfamily as other ETS factors display weaker binding. The AD binds to a single site on MED25 and the DBD interacts with three MED25 sites, allowing for simultaneous binding of both domains in full-length ETV4. MED25 also stimulates the in vitro DNA binding activity of ETV4 by relieving autoinhibition. ETV1/4/5 factors are often overexpressed in prostate cancer and genome-wide studies in a prostate cancer cell line indicate that ETV4 and MED25 occupy enhancers that are enriched for ETS-binding sequences and are both functionally important for the transcription of genes regulated by these enhancers. AP1-motifs, which bind JUN and FOS transcription factor families, were observed in MED25-occupied regions and JUN/FOS also contact MED25; FOS strongly binds to the same MED25 site as ETV4 AD and JUN interacts with the other two MED25 sites. In summary, we describe features of the multivalent ETV4- and AP1-MED25 interactions, thereby implicating these factors in the recruitment of MED25 to transcriptional control elements.


Assuntos
Proteínas E1A de Adenovirus/metabolismo , Complexo Mediador/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas E1A de Adenovirus/química , Linhagem Celular Tumoral , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Espectroscopia de Ressonância Magnética , Complexo Mediador/química , Modelos Biológicos , Simulação de Acoplamento Molecular , Ligação Proteica , Mapeamento de Interação de Proteínas , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas c-ets , Proteínas Proto-Oncogênicas c-fos/química
14.
Nat Commun ; 8: 14000, 2017 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-28128228

RESUMO

Stimulated emission is the process fundamental to laser operation, thereby producing coherent photon output. Despite negatively charged nitrogen-vacancy (NV-) centres being discussed as a potential laser medium since the 1980s, there have been no definitive observations of stimulated emission from ensembles of NV- to date. Here we show both theoretical and experimental evidence for stimulated emission from NV- using light in the phonon sidebands around 700 nm. Furthermore, we show the transition from stimulated emission to photoionization as the stimulating laser wavelength is reduced from 700 to 620 nm. While lasing at the zero-phonon line is suppressed by ionization, our results open the possibility of diamond lasers based on NV- centres, tuneable over the phonon sideband. This broadens the applications of NV- magnetometers from single centre nanoscale sensors to a new generation of ultra-precise ensemble laser sensors, which exploit the contrast and signal amplification of a lasing system.

15.
Nat Commun ; 8: 14482, 2017 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-28211538

RESUMO

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.

16.
Oncotarget ; 8(26): 42438-42454, 2017 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-28465491

RESUMO

Genomic alterations involving translocations of the ETS-related gene ERG occur in approximately half of prostate cancer cases. These alterations result in aberrant, androgen-regulated production of ERG protein variants that directly contribute to disease development and progression. This study describes the discovery and characterization of a new class of small molecule ERG antagonists identified through rational in silico methods. These antagonists are designed to sterically block DNA binding by the ETS domain of ERG and thereby disrupt transcriptional activity. We confirmed the direct binding of a lead compound, VPC-18005, with the ERG-ETS domain using biophysical approaches. We then demonstrated VPC-18005 reduced migration and invasion rates of ERG expressing prostate cancer cells, and reduced metastasis in a zebrafish xenograft model. These results demonstrate proof-of-principal that small molecule targeting of the ERG-ETS domain can suppress transcriptional activity and reverse transformed characteristics of prostate cancers aberrantly expressing ERG. Clinical advancement of the developed small molecule inhibitors may provide new therapeutic agents for use as alternatives to, or in combination with, current therapies for men with ERG-expressing metastatic castration-resistant prostate cancer.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Descoberta de Drogas , Motivo ETS , Neoplasias da Próstata/metabolismo , Domínios e Motivos de Interação entre Proteínas , Regulador Transcricional ERG/química , Regulador Transcricional ERG/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/genética , Descoberta de Drogas/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Modelos Moleculares , Conformação Molecular , Proteínas de Fusão Oncogênica/química , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Ligação Proteica , Relação Estrutura-Atividade , Regulador Transcricional ERG/genética , Peixe-Zebra
17.
Sci Rep ; 6: 19822, 2016 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-26805546

RESUMO

High surface area electrode materials are of interest for a wide range of potential applications such as super-capacitors and electrochemical cells. This paper describes a fabrication method of three-dimensional (3D) graphene conformally coated on nanoporous insulating substrate with uniform nanopore size. 3D graphene films were formed by controlled graphitization of diamond-like amorphous carbon precursor films, deposited by plasma-enhanced chemical vapour deposition (PECVD). Plasma-assisted graphitization was found to produce better quality graphene than a simple thermal graphitization process. The resulting 3D graphene/amorphous carbon/alumina structure has a very high surface area, good electrical conductivity and exhibits excellent chemically stability, providing a good material platform for electrochemical applications. Consequently very large electrochemical capacitance values, as high as 2.1 mF for a sample of 10 mm(3), were achieved. The electrochemical capacitance of the material exhibits a dependence on bias voltage, a phenomenon observed by other groups when studying graphene quantum capacitance. The plasma-assisted graphitization, which dominates the graphitization process, is analyzed and discussed in detail.

18.
Nanoscale ; 8(12): 6860-5, 2016 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-26956525

RESUMO

High quality, ultra-thin single crystal diamond (SCD) membranes that have a thickness in the sub-micron range are of extreme importance as a materials platform for photonics, quantum sensing, nano/micro electro-mechanical systems (N/MEMS) and other diverse applications. However, the scalable fabrication of such thin SCD membranes is a challenging process. In this paper, we demonstrate a new method which enables high quality, large size (∼4 × 4 mm) and low surface roughness, low strain, ultra-thin SCD membranes which can be fabricated without deformations such as breakage, bowing or bending. These membranes are easy to handle making them particularly suitable for fabrication of optical and mechanical devices. We demonstrate arrays of single crystal diamond membrane windows (SCDMW), each up to 1 × 1 mm in dimension and as thin as ∼300 nm, supported by a diamond frame as thick as ∼150 µm. The fabrication method is robust, reproducible, scalable and cost effective. Microwave plasma chemical vapour deposition is used for in situ creation of single nitrogen-vacancy (NV) centers into the thin SCDMW. We have also developed SCD drum head mechanical resonator composed of our fully clamped and freely suspended membranes.

19.
Sci Rep ; 5: 11486, 2015 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-26095793

RESUMO

We have developed a technique for creating high quality tellurite microspheres with embedded nanodiamonds (NDs) containing nitrogen-vacancy (NV) centres. This hybrid method allows fluorescence of the NVs in the NDs to be directly, rather than evanescently, coupled to the whispering gallery modes of the tellurite microspheres at room temperature. As a demonstration of its sensing potential, shifting of the resonance peaks is also demonstrated by coating a sphere surface with a liquid layer. This new approach is a robust way of creating cavities for use in quantum and sensing applications.

20.
Sci Rep ; 5: 11179, 2015 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-26109500

RESUMO

The negatively-charged nitrogen vacancy (NV(-)) center in diamond is of great interest for quantum information processing and quantum key distribution applications due to its highly desirable long coherence times at room temperature. One of the challenges for their use in these applications involves the requirement to further optimize the lifetime and emission properties of the centers. Our results demonstrate the reduction of the lifetime of NV(-) centers, and hence an increase in the emission rate, achieved by modifying the refractive index of the environment surrounding the nanodiamond (ND). By coating the NDs in a polymer film, experimental results and numerical calculations show an average of 63% reduction in the lifetime and an average enhancement in the emission rate by a factor of 1.6. This strategy is also applicable for emitters other than diamond color centers where the particle refractive index is greater than the refractive index of the surrounding media.

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