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1.
Phys Rev Lett ; 124(12): 120402, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32281831

RESUMO

We show-both theoretically and experimentally-that Einstein-Podolsky-Rosen steering can be distilled. We present a distillation protocol that outputs a perfectly correlated system-the singlet assemblage-in the asymptotic infinite-copy limit, even for inputs that are arbitrarily close to being unsteerable. As figures of merit for the protocol's performance, we introduce the assemblage fidelity and the singlet-assemblage fraction. These are potentially interesting quantities on their own beyond the current scope. Remarkably, the protocol works well also in the nonasymptotic regime of few copies, in the sense of increasing the singlet-assemblage fraction. We demonstrate the efficacy of the protocol using a hyperentangled photon pair encoding two copies of a two-qubit state. This represents to our knowledge the first observation of deterministic steering concentration. Our findings are not only fundamentally important but may also be useful for semi-device-independent protocols in noisy quantum networks.

2.
Phys Rev Lett ; 120(14): 140408, 2018 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-29694116

RESUMO

We theoretically predict, and experimentally verify with entangled photons, that outcome communication is not enough for hidden-state models to reproduce quantum steering. Hidden-state models with outcome communication correspond, in turn, to the well-known instrumental processes of causal inference but in the one-sided device-independent scenario of one black-box measurement device and one well-characterized quantum apparatus. We introduce one-sided device-independent instrumental inequalities to test against these models, with the appealing feature of detecting entanglement even when communication of the black box's measurement outcome is allowed. We find that, remarkably, these inequalities can also be violated solely with steering, i.e., without outcome communication. In fact, an efficiently computable formal quantifier-the robustness of noninstrumentality-naturally arises, and we prove that steering alone is enough to maximize it. Our findings imply that quantum theory admits a stronger form of steering than known until now, with fundamental as well as practical potential implications.

3.
Sleep Breath ; 19(4): 1213-20, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25682270

RESUMO

PURPOSE: Evaluation of the effects of rapid maxillary expansion and mandibular advancement using Propulsor Universal Light appliance on the upper airways in Marfan's syndrome children through home sleep studies, Epworth Sleepiness Scale questionnaire, and cephalometric analysis of the upper airways on lateral radiographs. METHODS: The study sample consisted of 30 children with Marfan's syndrome, and the control group consisted of 30 untreated and matched children. For Marfan subjects, data were taken at different time points compared to treatment: at T0 (before treatment), T1 (after rapid maxillary expansion), and T2 (after mandibular advancement). For control subjects, data were taken at similar intervals, at three follow-up visits: at T0 (as a starting screening tool), T1 (after approximately 2 years), and T2 (in proximity of the peak skeletal growth). RESULTS: Apnea-hypopnea and oxygen desaturations were significantly higher in the study group at T0 and T1 compared with control children. At T2, the values were not significant (p value 0.442 for both apnea-hypopnea index (AHI) and oxygen desaturation index (ODI)). Horizontal airway dimensions were significantly reduced, and vertical airway values were significantly increased in Marfan's syndrome at T0 and T1 but not at T2 (p values at T2: 0.071 for Phw1-Psp, 0.106 for Phw1-Psp', 0.101 for Phw2-Tb, 0.559 for UAL in male and 0.560 for UAL in female). CONCLUSIONS: Early rapid maxillary expansion and mandibular advancement using Propulsor Universal Light appliance significantly improved airway patency of Marfan's syndrome children and are strongly encouraged as a routine treatment for both correction of class II malocclusions and prevention of obstructive sleep apnea.


Assuntos
Cefalometria , Avanço Mandibular/métodos , Síndrome de Marfan/fisiopatologia , Síndrome de Marfan/cirurgia , Aparelhos Ortodônticos , Técnica de Expansão Palatina/instrumentação , Polissonografia , Ventilação Pulmonar/fisiologia , Apneia Obstrutiva do Sono/fisiopatologia , Apneia Obstrutiva do Sono/cirurgia , Estudos de Casos e Controles , Criança , Feminino , Seguimentos , Humanos , Masculino , Avanço Mandibular/instrumentação , Desenho de Aparelho Ortodôntico
4.
Phys Rev Lett ; 110(5): 050402, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23414007

RESUMO

The evaluation of the minimal evolution time between two distinguishable states of a system is important for assessing the maximal speed of quantum computers and communication channels. Lower bounds for this minimal time have been proposed for unitary dynamics. Here we show that it is possible to extend this concept to nonunitary processes, using an attainable lower bound that is connected to the quantum Fisher information for time estimation. This result is used to delimit the minimal evolution time for typical noisy channels.

5.
J Pathol ; 226(2): 380-93, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21953325

RESUMO

Anoikis is a programmed cell death occurring upon cell detachment from the correct extracellular matrix, thus disrupting integrin ligation. It is a critical mechanism in preventing dysplastic cell growth or attachment to an inappropriate matrix. Anoikis prevents detached epithelial cells from colonizing elsewhere and is thus essential for tissue homeostasis and development. As anchorage-independent growth and epithelial-mesenchymal transition, two features associated with anoikis resistance, are crucial steps during tumour progression and metastatic spreading of cancer cells, anoikis deregulation has now evoked particular attention from the scientific community. The aim of this review is to analyse the molecular mechanisms governing both anoikis and anoikis resistance, focusing on their regulation in physiological processes, as well as in several diseases, including metastatic cancers, cardiovascular diseases and diabetes.


Assuntos
Anoikis/fisiologia , Doenças Cardiovasculares/patologia , Diabetes Mellitus/patologia , Neoplasias/patologia , Anoikis/efeitos dos fármacos , Transplante de Células/métodos , Humanos
6.
Cell Death Differ ; 15(5): 867-78, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18259192

RESUMO

Proper attachment to the extracellular matrix (ECM) is essential for cell survival. The loss of integrin-mediated cell-ECM contact results in an apoptotic process termed anoikis. However, mechanisms involved in regulation of cell survival are poorly understood and mediators responsible for anoikis have not been well characterized. Here, we demonstrate that reactive oxygen species (ROS) produced through the involvement of the small GTPase Rac-1 upon integrin engagement exert a mandatory role in transducing a pro-survival signal that ensures that cells escape from anoikis. In particular, we show that ROS are responsible for the redox-mediated activation of Src that trans-phosphorylates epidermal growth factor receptor (EGFR) in a ligand-independent manner. The redox-dependent phosphorylation of EGFR activates both extracellular signal-regulated protein kinase and Akt downstream signalling pathways, culminating in degradation of the pro-apoptotic protein Bim. Hence, our results shed new light on the mechanism granting the adhesion-dependent antiapoptotic effect, highlighting a fundamental role of ROS-mediated Src regulation in ensuring anoikis protection.


Assuntos
Anoikis/fisiologia , Sobrevivência Celular/fisiologia , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Adesão Celular/fisiologia , Linhagem Celular , Ativação Enzimática , Receptores ErbB/metabolismo , Matriz Extracelular/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Integrinas/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/fisiologia , Ativação Transcricional , Proteínas rac1 de Ligação ao GTP/metabolismo , Quinases da Família src/metabolismo
7.
Mol Biol Cell ; 16(1): 73-83, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15525682

RESUMO

Cellular behavior can be considered to be the result of a very complex spatial and temporal integration of intracellular and extracellular signals. These signals arise from serum-soluble factors as well as from cell-substrate or cell-cell interactions. The current approach in mitogenesis studies is generally to analyze the effect of a single growth factor on serum-starved cells. In this context, a metabolic hormone such as insulin is found to be a mitogenic agent in many cellular types. In the present study, we have considered the effect of insulin stimulation in platelet-derived growth factor (PDGF)-activated NIH-3T3 and C2C12 cells. Our results show that insulin is able to inhibit strongly both NIH-3T3 and C2C12 cell growth induced by PDGF, one of the most powerful mitotic agents for these cell types. This inhibitory effect of insulin is due primarily to a premature down-regulation of the PDGF receptor. Thus, when NIH-3T3 or C2C12 cells are stimulated with both PDGF and insulin, we observe a decrease in PDGF receptor phosphorylation with respect to cells treated with PDGF alone. In particular, we find that costimulation with insulin leads to a reduced production of H2O2 with respect to cell stimulation with PDGF alone. The relative low concentration of H2O2 in PDGF/insulin-costimulated cell leads to a limited down-regulation of protein tyrosine phosphatases, and, consequently, to a reduced PDGF receptor phosphorylation efficiency. The latter is very likely to be responsible for the insulin-dependent inhibition of PDGF-receptor mitogenic signaling.


Assuntos
Insulina/metabolismo , Fator de Crescimento Derivado de Plaquetas/metabolismo , Animais , Anti-Infecciosos Locais/farmacologia , Comunicação Celular , Linhagem Celular , Proliferação de Células , Meios de Cultura Livres de Soro/farmacologia , Regulação para Baixo , Endocitose , Violeta Genciana/farmacologia , Peróxido de Hidrogênio/farmacologia , Imunoprecipitação , Camundongos , Mitose , Células NIH 3T3 , Oxirredução , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Espécies Reativas de Oxigênio , Receptor de Insulina/metabolismo , Receptores do Fator de Crescimento Derivado de Plaquetas/metabolismo , Timidina/farmacologia , Fatores de Tempo , Tirosina/química , Tirosina/metabolismo , Quinases da Família src/metabolismo
8.
Nat Commun ; 8(1): 809, 2017 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-28993649

RESUMO

Since its commercial introduction three-quarters of a century ago, fluid catalytic cracking has been one of the most important conversion processes in the petroleum industry. In this process, porous composites composed of zeolite and clay crack the heavy fractions in crude oil into transportation fuel and petrochemical feedstocks. Yet, over time the catalytic activity of these composite particles decreases. Here, we report on ptychographic tomography, diffraction, and fluorescence tomography, as well as electron microscopy measurements, which elucidate the structural changes that lead to catalyst deactivation. In combination, these measurements reveal zeolite amorphization and distinct structural changes on the particle exterior as the driving forces behind catalyst deactivation. Amorphization of zeolites, in particular, close to the particle exterior, results in a reduction of catalytic capacity. A concretion of the outermost particle layer into a dense amorphous silica-alumina shell further reduces the mass transport to the active sites within the composite.Catalyst deactivation in fluid catalytic cracking processes is unavoidably associated with structural changes. Here, the authors visualize the deactivation of zeolite catalysts by ptychography and other imaging techniques, showing pronounced amorphization of the outer layer of the catalyst particles.

9.
Org Lett ; 3(3): 337-40, 2001 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-11428008

RESUMO

[figure: see text] beta-Lactams were prepared on solid phase starting from serine, threonine, or other beta-hydroxyacids derived from naturally occurring amino acids and a resin bound hydroxylamine. The ring closure was carried out under Mitsunobu conditions. The amino group present on the beta-lactam was used to assemble a short peptide. After a reductive cleavage with Sml2, beta-lactam-containing peptides were obtained.


Assuntos
Antibacterianos/síntese química , Ácidos Hidroxâmicos/química , beta-Lactamas/síntese química , Hidroxilaminas , Poliestirenos , Serina/química , Treonina/química
10.
Org Lett ; 3(21): 3273-5, 2001 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-11594812

RESUMO

[reaction: see text]. Enantiomerically pure (S)-cleonin, a key component of the antitumor antibiotic cleomycin, was prepared starting from (R)-serine. The Kulinkovich cyclopropanation of the methyl ester of N-Cbz serine acetonide gave the hydroxycyclopropyl moiety. The amino alcohol region was further oxidized to amino acid. The Kulinkovich cyclopropanation allowed also the preparation of other non-natural substituted cyclopropylglycines.


Assuntos
Aminoácidos/síntese química , Bleomicina/análogos & derivados , Ciclopropanos/síntese química , Antibióticos Antineoplásicos/síntese química , Bleomicina/síntese química , Estereoisomerismo
11.
Org Lett ; 3(6): 855-7, 2001 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-11263899

RESUMO

A new polymer-supported radical source was developed by loading an N-hydroxy thiazole 2(3)-thione on a Wang resin. This new supported reagent can be employed for a solid-phase version of the Hunsdiecker reaction or to liberate free alkoxy radicals, in a variant of the "catch and release" technique, under very mild conditions (irradiation with a discharge lamp) and simplifying the purification procedure.

12.
J Clin Pathol ; 39(2): 125-8, 1986 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3485115

RESUMO

Thirty two unrelated Italian subjects with idiopathic haemochromatosis were studied. HLA-A3 was present in 26 of them (81% v 22% in controls; p less than 0.001) and HLA B7 in eight (28% v 9%; p less than 0.01). There was no important association between idiopathic haemochromatosis and HLA B14. Subdividing the patients on the basis of their regional origin a noticeably higher prevalence of HLA Bw35 in patients with idiopathic haemochromatosis from north eastern Italy was found than in those from Lombardy, or in the controls; there were no differences in the incidence of HLA A3 and B7 between patients with idiopathic haemochromatosis from different areas. A high prevalence of A3, Bw35, and A3, B7 haplotypes was found in our patients with idiopathic haemochromatosis. A3, Bw35 could be the haplotype most commonly linked to the idiopathic haemochromatosis gene in north eastern Italy.


Assuntos
Marcadores Genéticos , Antígenos HLA/genética , Hemocromatose/imunologia , Adulto , Feminino , Ferritinas/sangue , Antígeno HLA-A3 , Antígeno HLA-B35 , Antígeno HLA-B7 , Hemocromatose/genética , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Transferrina/metabolismo
13.
J Inorg Biochem ; 85(2-3): 79-87, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11410227

RESUMO

The studies on binding ability of longer chiral peptide nucleic acids (having four, six and eight thymines in a peptide side chain) have shown that the interactions between the nucleic base rings within a ligand molecule have a critical impact on the complex stability. Thymines inserted in the peptide side chain interact with each other as well as with peptide back-bone increasing the structural organization of the cPNA molecule. The metal ion coordination to cPNA, on the other hand, induces a very specific ligand structure, which may have a basic impact on the cPNA self-recognition processes.


Assuntos
Cobre/farmacologia , Níquel/farmacologia , Ácidos Nucleicos Peptídicos/química , Timina/metabolismo , Cobre/metabolismo , Estabilidade de Medicamentos , Modelos Moleculares , Estrutura Molecular , Níquel/metabolismo , Ácidos Nucleicos Peptídicos/metabolismo , Estrutura Secundária de Proteína/efeitos dos fármacos , Estereoisomerismo
14.
Methods Mol Med ; 23: 189-207, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-21380899

RESUMO

Oligopeptides containing an oxirane ring have recently been identified as inhibitors of a variety of proteases (1-3). These peptidomimetics have the potential to coordinate with metal present in the active site and, after nucleophilic ring opening, irreversibly blocking the enzyme. For this reason, oxirane containing peptidomimetics are good candidates to became transition states analogs or suicide inhibitors with long term efficacy in vivo (3). Synthetic routes to a variety of terminal (4-8) and internal epoxide peptidomimetics (9-11) have been reported but there are no examples of incorporation of such epoxides into oligopeptides. The focus of this chapter will be on the preparation of oligopeptides (up to a three-peptide) containing an epoxide in the place of the peptide bond. The structures prepared here can be identified, using the notation suggested by Spatola (12) as AAxψ[traws-epoxy]-AAy. The general synthetic approach described in this chapter is based on the aldol type reaction of a silylketene thioacetal and a ß-amino α-selenyl aldehyde derived from an oligopeptide. This reaction stereoselectively generates a vicinal hydroxy selenide which can be further oxidized to epoxide (Fig. 1). Fig. 1. Retrosynthetic analysis of oxirane peptidomimetrics.

15.
Arch Gerontol Geriatr ; 22 Suppl 1: 271-4, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-18653043

RESUMO

The influence of diabetic treatment regimens on vitamin D metabolism and on bone mineral content has been explored in 41 elderly patients with normal renal and hepatic functions. The data obtained suggest that oral treatment with hypoglycemic compounds exerts a negative influence on vitamin D metabolism. It is possible that the reduction of 25-OH-hydroxy-vitamin D levels depends on a high conversion rate to the active 1,25-dihydroxy-vitamin D, as a consequence of parathormone-stimulated increase of 1-alpha-hydroxylase activity. On the other hand, no differences in bone mineral densities were observed in correlation with the diabetic treatment regimens. Therefore, oral treatment with hypoglycemic compounds can only be associated with an accelerated vitamin D metabolism.

16.
Minerva Chir ; 51(3): 109-20, 1996 Mar.
Artigo em Italiano | MEDLINE | ID: mdl-8684649

RESUMO

We examined in this perspective study 30 patients (15 males and 15 females) who undergone classic thoracotomy for lung or mediastinal diseases, without postoperative complications. Intensity and different qualitative components of postoperative pain have been evaluated in the 1st, 3rd, 5th, the day after last pleural drainage removal and 2 months after the operation. All patients answered a schedule adherent to Questionario Italiano del Dolore (QUID). Pain became less intense chiefly with drainage removal with the same time trend for both sex (parallel curves). Pain is probably stronger in women. From a qualitative point of view, the sensorial component is the same in both sexes. Affective and evaluative component is greater in women: in other words, women realize more than men the painful stimulus and are more troubled. A computerized analysis of answers to a questionnaire like QUID or, better, its evolution, may be helpful for a more effective pharmacological choice between pure analgesics, sedative analgesics and ataractic drugs.


Assuntos
Dor Pós-Operatória/etiologia , Toracotomia/efeitos adversos , Analgésicos/uso terapêutico , Diagnóstico por Computador , Feminino , Humanos , Hipnóticos e Sedativos/uso terapêutico , Masculino , Pessoa de Meia-Idade , Medição da Dor , Dor Pós-Operatória/diagnóstico , Dor Pós-Operatória/tratamento farmacológico , Fatores Sexuais
17.
Appl Radiat Isot ; 77: 50-5, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23524230

RESUMO

A radiochemical method has been adapted to determine (59)Ni and (63)Ni in samples of radioactive wastes from the water cleanup system of the IEA-R1 nuclear research reactor. The process includes extraction chromatographic resin with dimethylglyoxime (DMG) as a functional group. Activity concentrations of (59)Ni and (63)Ni were measured, respectively, by X-ray spectrometry and liquid scintillation counting, whereas the chemical yield was determined by ICP-OES. The average ratio of measured activity concentrations of (63)Ni and (59)Ni agree well with theory.


Assuntos
Carvão Vegetal/química , Resinas de Troca Iônica/química , Níquel/análise , Resíduos Radioativos/análise , Radioisótopos/análise , Radiometria/métodos , Brasil , Carvão Vegetal/análise , Resinas de Troca Iônica/análise , Teste de Materiais/métodos , Níquel/química , Doses de Radiação , Radioisótopos/química
18.
Radiat Prot Dosimetry ; 144(1-4): 124-9, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21123238

RESUMO

In recent years, Brazilian Nuclear Programme has been reviewed and updated by government authorities in face of the demand for energy supply and its associated environmental constraints. The immediate impact of new national programmes and projects in nuclear field is the increase in the number of exposed personnel and the consequent need for reliable dosimetry services in the country. Several Technical Documents related to internal dosimetry have been released by the International Atomic Energy Agency and International Commission on Radiological Protection. However, standard bioassay procedures and methodologies for bioassay data interpretation are still under discussion and, in some cases, both in routine and emergency internal monitoring, procedures can vary from one laboratory to another and responses may differ markedly among Dosimetry Laboratories. Thus, it may be difficult to interpret and use bioassay data generated from different laboratories of a network. The main goal of this work is to implement a National Network of Laboratories aimed to provide reliable internal monitoring services in Brazil. The establishment of harmonised in vivo and in vitro radioanalytical techniques, dose assessment methods and the implementation of the ISO/IEC 17025 requirements will result in the recognition of technical competence of the network.


Assuntos
Exposição Ocupacional/prevenção & controle , Monitoramento de Radiação/normas , Proteção Radiológica/normas , Radiometria/normas , Acreditação , Bioensaio/métodos , Brasil , Geografia , Humanos , Centrais Nucleares , Controle de Qualidade , Monitoramento de Radiação/métodos , Proteção Radiológica/métodos , Radiometria/métodos
20.
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