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1.
Opt Express ; 26(12): 14905-14914, 2018 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-30114795

RESUMEN

We demonstrate the operation of a closed-loop fast-light cavity that allows rapid (~10 ms) measurements of the cavity mode frequency and its uncertainty. We vary the scale factor by temperature tuning the atomic density of an intracavity vapor cell. The cavity remains locked even as the system passes through the critical anomalous dispersion where a pole is observed in the scale factor. Positive and negative scale-factor enhancements as large as |S| ≈70 were obtained. To our knowledge, these are the first experiments that demonstrate a scale-factor enhancement in a closed-loop fast-light device by changing the optical path length, laying the groundwork for the improvement of cavity-based metrology instruments such as optical gyroscopes.

2.
Phys Rev Lett ; 115(18): 182501, 2015 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-26565463

RESUMEN

In the standard model, the weak interaction is formulated with a purely vector-axial-vector (V-A) structure. Without restriction on the chirality of the neutrino, the most general limits on tensor currents from nuclear ß decay are dominated by a single measurement of the ß-ν[over ¯] correlation in ^{6}He ß decay dating back over a half century. In the present work, the ß-ν[over ¯]-α correlation in the ß decay of ^{8}Li and subsequent α-particle breakup of the ^{8}Be^{*} daughter was measured. The results are consistent with a purely V-A interaction and in the case of couplings to right-handed neutrinos (C_{T}=-C_{T}^{'}) limits the tensor fraction to |C_{T}/C_{A}|^{2}<0.011 (95.5% C.L.). The measurement confirms the ^{6}He result using a different nuclear system and employing modern ion-trapping techniques subject to different systematic uncertainties.

3.
Phys Rev Lett ; 115(13): 132502, 2015 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-26451549

RESUMEN

Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and 247(73) µs have been discovered in the heavy ^{254}Rf nucleus. The observation of the shorter-lived isomer was made possible by a novel application of a digital data acquisition system. The isomers were interpreted as the K^{π}=8^{-}, ν^{2}(7/2^{+}[624],9/2^{-}[734]) two-quasineutron and the K^{π}=16^{+}, 8^{-}ν^{2}(7/2^{+}[624],9/2^{-}[734])⊗8^{-}π^{2}(7/2^{-}[514],9/2^{+}[624]) four-quasiparticle configurations, respectively. Surprisingly, the lifetime of the two-quasiparticle isomer is more than 4 orders of magnitude shorter than what has been observed for analogous isomers in the lighter N=150 isotones. The four-quasiparticle isomer is longer lived than the ^{254}Rf ground state that decays exclusively by spontaneous fission with a half-life of 23.2(1.1) µs. The absence of sizable fission branches from either of the isomers implies unprecedented fission hindrance relative to the ground state.

4.
Phys Rev Lett ; 112(15): 152701, 2014 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-24785033

RESUMEN

The 1809-keV γ ray from the decay of (26)Al(g) is an important target for γ-ray astronomy. In the convective C/Ne burning shell of massive presupernova stars, the (23)Na(α,p)(26)Mg reaction directly influences the production of (26)Al. We have performed a direct measurement of the (23)Na(α,p)(26)Mg reaction cross section at the appropriate astrophysically important energies. The stellar rate calculated in the present work is larger than the recommended rate by nearly a factor of 40 and could strongly affect the production of (26)Al in massive stars.

5.
Phys Rev Lett ; 112(19): 192701, 2014 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-24877935

RESUMEN

The interaction between neutron-rich nuclei plays an important role for understanding the reaction mechanism of the fusion process as well as for the energy production through pycnonuclear reactions in the crust of neutron stars. We have performed the first measurements of the total fusion cross sections in the systems (10,14,15)C+(12)C using a new active target-detector system. In the energy region accessible with existing radioactive beams, a good agreement between the experimental and theoretical cross sections is observed. This gives confidence in our ability to calculate fusion cross sections for systems which are outside the range of today's radioactive beam facilities.

6.
Phys Rev Lett ; 113(26): 262505, 2014 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-25615317

RESUMEN

We report on the first measurement of the fission barrier height in a heavy shell-stabilized nucleus. The fission barrier height of 254No is measured to be Bf=6.0±0.5 MeV at spin 15ℏ and, by extrapolation, Bf=6.6±0.9 MeV at spin 0ℏ. This information is deduced from the measured distribution of entry points in the excitation energy versus spin plane. The same measurement is performed for 220Th and only a lower limit of the fission barrier height can be determined: Bf(I)>8 MeV. Comparisons with theoretical fission barriers test theories that predict properties of superheavy elements.

7.
Phys Rev Lett ; 111(6): 061102, 2013 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-23971550

RESUMEN

The Canadian Penning Trap mass spectrometer has made mass measurements of 33 neutron-rich nuclides provided by the new Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory. The studied region includes the 132Sn double shell closure and ranges in Z from In to Cs, with Sn isotopes measured out to A=135, and the typical measurement precision is at the 100 ppb level or better. The region encompasses a possible major waiting point of the astrophysical r process, and the impact of the masses on the r process is shown through a series of simulations. These first-ever simulations with direct mass information on this waiting point show significant increases in waiting time at Sn and Sb in comparison with commonly used mass models, demonstrating the inadequacy of existing models for accurate r-process calculations.

8.
Phys Rev Lett ; 110(9): 092501, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23496704

RESUMEN

A novel technique for ß-delayed neutron spectroscopy has been demonstrated using trapped ions. The neutron-energy spectrum is reconstructed by measuring the time of flight of the nuclear recoil following neutron emission, thereby avoiding all the challenges associated with neutron detection, such as backgrounds from scattered neutrons and γ rays and complicated detector-response functions. (137)I(+) ions delivered from a (252)Cf source were confined in a linear Paul trap surrounded by radiation detectors, and the ß-delayed neutron-energy spectrum and branching ratio were determined by detecting the ß(-) and recoil ions in coincidence. Systematic effects were explored by determining the branching ratio three ways. Improvements to achieve higher detection efficiency, better energy resolution, and a lower neutron-energy threshold are proposed.

9.
Phys Rev Lett ; 110(9): 092502, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23496705

RESUMEN

A measurement of the α-ß-ν[over ¯] angular correlation in the Gamow-Teller decay (8)Li→(8)Be(*)+ν[over ¯]+ß, (8)Be(*)→α+α has been performed using ions confined in a linear Paul trap surrounded by silicon detectors. The energy difference spectrum of the α particles emitted along and opposite the direction of the ß particle is consistent with the standard model prediction and places a limit of 3.1% (95.5% confidence level) on any tensor contribution to the decay. From this result, the amplitude of any tensor component C(T) relative to that of the dominant axial-vector component C(A) of the electroweak interaction is limited to |C(T)/C(A)|<0.18 (95.5% confidence level). This experimental approach is facilitated by several favorable features of the (8)Li ß decay and has different systematic effects than the previous ß-ν[over ¯] correlation results for a pure Gamow-Teller transition obtained from studying (6)He ß decay.

10.
Nat Genet ; 26(3): 283-9, 2000 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11062466

RESUMEN

We have developed a novel protein chip technology that allows the high-throughput analysis of biochemical activities, and used this approach to analyse nearly all of the protein kinases from Saccharomyces cerevisiae. Protein chips are disposable arrays of microwells in silicone elastomer sheets placed on top of microscope slides. The high density and small size of the wells allows for high-throughput batch processing and simultaneous analysis of many individual samples. Only small amounts of protein are required. Of 122 known and predicted yeast protein kinases, 119 were overexpressed and analysed using 17 different substrates and protein chips. We found many novel activities and that a large number of protein kinases are capable of phosphorylating tyrosine. The tyrosine phosphorylating enzymes often share common amino acid residues that lie near the catalytic region. Thus, our study identified a number of novel features of protein kinases and demonstrates that protein chip technology is useful for high-throughput screening of protein biochemical activity.


Asunto(s)
Proteínas Fúngicas/análisis , Perfilación de la Expresión Génica/instrumentación , Proteínas Tirosina Quinasas/análisis , Saccharomyces cerevisiae/enzimología , Adenosina Trifosfato/metabolismo , Diseño de Equipo , Evolución Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/aislamiento & purificación , Proteínas Fúngicas/metabolismo , Perfilación de la Expresión Génica/métodos , Regulación Enzimológica de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Péptidos/metabolismo , Radioisótopos de Fósforo/análisis , Fosforilación , Conformación Proteica , Procesamiento Proteico-Postraduccional , Estructura Terciaria de Proteína , Proteínas Tirosina Quinasas/química , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas/aislamiento & purificación , Proteínas Tirosina Quinasas/metabolismo , Proteínas/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Alineación de Secuencia , Análisis de Secuencia de Proteína , Especificidad por Sustrato
11.
Phys Rev Lett ; 106(17): 172701, 2011 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-21635032

RESUMEN

The structure of (15)C, with an s(1/2) neutron weakly bound to a closed-neutron shell nucleus (14)C, makes it a prime candidate for a one-neutron halo nucleus. We have for the first time studied the cross section for the fusion-fission reaction (15)C+(232)Th at energies in the vicinity of the Coulomb barrier and compared it to the yield of the neighboring (14)C+(232)Th system measured in the same experiment. At sub-barrier energies, an enhancement of the fusion yield by factors of 2-5 was observed for (15)C, while the cross sections for (14)C match the trends measured for (12,13)C.

14.
Science ; 293(5537): 2101-5, 2001 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-11474067

RESUMEN

To facilitate studies of the yeast proteome, we cloned 5800 open reading frames and overexpressed and purified their corresponding proteins. The proteins were printed onto slides at high spatial density to form a yeast proteome microarray and screened for their ability to interact with proteins and phospholipids. We identified many new calmodulin- and phospholipid-interacting proteins; a common potential binding motif was identified for many of the calmodulin-binding proteins. Thus, microarrays of an entire eukaryotic proteome can be prepared and screened for diverse biochemical activities. The microarrays can also be used to screen protein-drug interactions and to detect posttranslational modifications.


Asunto(s)
Proteínas Fúngicas/metabolismo , Proteoma , Saccharomyces cerevisiae/metabolismo , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Calmodulina/metabolismo , Proteínas de Unión a Calmodulina/metabolismo , Membrana Celular/metabolismo , Clonación Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glucosa/metabolismo , Liposomas/metabolismo , Proteínas de la Membrana/metabolismo , Datos de Secuencia Molecular , Sistemas de Lectura Abierta , Biblioteca de Péptidos , Fosfatidilcolinas/metabolismo , Fosfatidilinositoles/metabolismo , Fosfolípidos/metabolismo , Unión Proteica , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Transducción de Señal , Estreptavidina/metabolismo
15.
J Subst Abuse Treat ; 87: 56-63, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29471927

RESUMEN

Motivational Interviewing (MI) is an evidence-based practice shown to be effective when working with people in treatment for substance use disorders. However, MI is a complex treatment modality optimized by training with feedback. Feedback, assessment and monitoring of treatment fidelity require measurement, which is typically done using audiotaped sessions. The gold standard for such measurement of MI skill has been an audiotaped interview, scored by a rater with a detailed structured instrument such as the Motivational Interviewing Treatment Integrity 2.0 (MITI 2.0) Coding System (Moyers, et al., 2005). The Helpful Responses Questionnaire (HRQ) (Miller, Hedrick, & Orlofsky, 1991) is a pen-and-paper test of empathy (a foundational MI skill) that does not require an audiotaped session. A randomized trial of three different regimens for training counselors in MI (live supervision using Teleconferencing, Tape-based supervision and Workshop only) (Smith et al., 2012) offered the opportunity to evaluate the performance of the HRQ as a measure of MI ability, compared to the several MITI 2.0 global scores and subscales. Participants were counselors (N=97) working at community-based substance use treatment programs, whose MI proficiency was measured at four time points: baseline (before an initial 2-day MI workshop), post-workshop, 8weeks post-workshop (i.e., post-supervision), and 20weeks post-workshop with both MITI 2.0 and HRQ. HRQ total scores correlated significantly with the Reflection to Question Ratio from the MITI 2.0 at post-workshop (r=0.33), week 8 (r=0.34), and week 20 (r=0.38), and with the Spirit (r=0.32) and Empathy (r=0.32) global scores at week 20. Correlations of HRQ with other MITI 2.0 subscales and time points after workshop were small and not significant. As predicted, HRQ scores differed between training conditions (X2(2)=7.88, p=0.02), with counselors assigned to live supervision achieving better HRQ scores than those in Workshop only. In summary, HRQ is a modestly accurate measure, mainly of the Reflection to Question Ratio, considered a core marker of MI skill. It is sensitive to training effects and may help identify counselors needing more intensive supervision. Given its ease of administration and scoring, HRQ may be a useful marker of MI skill during training efforts.


Asunto(s)
Competencia Clínica , Consejo/educación , Empatía , Entrevista Motivacional , Trastornos Relacionados con Sustancias/rehabilitación , Adolescente , Adulto , Femenino , Humanos , Entrevistas como Asunto , Masculino , Persona de Mediana Edad , Centros de Tratamiento de Abuso de Sustancias , Encuestas y Cuestionarios , Resultado del Tratamiento , Adulto Joven
16.
G Chir ; 28(1-2): 20-4, 2007.
Artículo en Italiano | MEDLINE | ID: mdl-17313728

RESUMEN

Desmoid tumors are rare benign neoplasms with high tendency to local recurrence, and they can be divided into extra- and intra-abdominal types (mesenteric fibromatosis). Eight cases have been treated in our Department from 1997 to 2006. Six patients (3 men and 3 women) affected by extra-abdominal desmoid tumors have been treated with radical excision. In two patients desmoid was intra-abdominal: 1) a 55 years old man admitted for acute abdomen and submitted, in emergency, to a laparotomy with excision of a mesenteric abscess including a jejunal loop at about one meter from Treitz; 2) 52 years old man, submitted to an elective excision of a capsulated neoplasm of the little omentum, which had caused an oppressive abdominal pain. In both cases the hystological diagnosis has been desmoid tumor. Surgical treatment of desmoid tumors must aim at radical excision to avoid frequent recurrences (25-65%); these have stimulated the research of other kinds of treatments, since a new surgical operation itself can lead to a further recurrence. Radiotherapy has been investigated with results in 79-96% of cases, antiestrogenic therapy has been used with success in 51% of patients, and high dose tamoxifen seemed to obtain a stable disease in non operable cases. Non steroidal anti-inflammatory drugs have been experimented in association with tamoxifen and chemotherapy. Conclusive results on the efficacy of these treatments have not been obtained yet, because of the rarity of the desmoid tumors even in greater Centres.


Asunto(s)
Fibromatosis Abdominal/cirugía , Mesenterio , Neoplasias Peritoneales/cirugía , Neoplasias Abdominales/patología , Neoplasias Abdominales/cirugía , Anciano , Femenino , Fibromatosis Abdominal/patología , Fibromatosis Agresiva/cirugía , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Peritoneales/patología , Estudios Retrospectivos , Resultado del Tratamiento
17.
G Chir ; 28(4): 149-52, 2007 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-17475117

RESUMEN

Unilateral phrenic nerve paralysis is a rare complication of cervico-mediastinal goitre. It occurs when adhesions grow between the intrathoracic part of the thyroid and the nerve, specially where the goitre enters the mediastinum behind the first rib. The damage may be caused by strain of the nerve due to the descent of the goitre into the chest or may be caused by the surgical manoeuvres during thyroidectomy performed by cervical approach. Two patients operated on for large cervico-mediastinal goitre are reported: a 70-year-old male with a large intrathoracic growth of the left thyroid lobe and a 54-year-old male with a large intrathoracic growth to the right lobe. A few days after total thyroidectomy they showed signs of exertional dyspnoea. The exams performed showed hemi-diaphragm relaxatio due to phrenic nerve paralysis, with resulting reduction of respiratory space. Phrenic nerve paralysis may follow total thyroidectomy for large cervico-mediastinal goitres; is not due to the operative technique, but rather to the particular anatomic conditions which may be found.


Asunto(s)
Bocio/cirugía , Parálisis/etiología , Enfermedades del Sistema Nervioso Periférico/etiología , Nervio Frénico , Tiroidectomía/efectos adversos , Anciano , Bocio/patología , Humanos , Masculino , Persona de Mediana Edad , Tiroidectomía/métodos
18.
Nucleic Acids Res ; 30(20): 4574-82, 2002 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-12384605

RESUMEN

We present a prototype of a new database tool, GeneCensus, which focuses on comparing genomes globally, in terms of the collective properties of many genes, rather than in terms of the attributes of a single gene (e.g. sequence similarity for a particular ortholog). The comparisons are presented in a visual fashion over the web at GeneCensus.org. The system concentrates on two types of comparisons: (i) trees based on the sharing of generalized protein families between genomes, and (ii) whole pathway analysis in terms of activity levels. For the trees, we have developed a module (TreeViewer) that clusters genomes in terms of the folds, superfamilies or orthologs--all can be considered as generalized 'families' or 'protein parts'--they share, and compares the resulting trees side-by-side with those built from sequence similarity of individual genes (e.g. a traditional tree built on ribosomal similarity). We also include comparisons to trees built on whole-genome dinucleotide or codon composition. For pathway comparisons, we have implemented a module (PathwayPainter) that graphically depicts, in selected metabolic pathways, the fluxes or expression levels of the associated enzymes (i.e. generalized 'activities'). One can, consequently, compare organisms (and organism states) in terms of representations of these systemic quantities. Develop ment of this module involved compiling, calculating and standardizing flux and expression information from many different sources. We illustrate pathway analysis for enzymes involved in central metabolism. We are able to show that, to some degree, flux and expression fluctuations have characteristic values in different sections of the central metabolism and that control points in this system (e.g. hexokinase, pyruvate kinase, phosphofructokinase, isocitrate dehydrogenase and citric synthase) tend to be especially variable in flux and expression. Both the TreeViewer and PathwayPainter modules connect to other information sources related to individual-gene or organism properties (e.g. a single-gene structural annotation viewer).


Asunto(s)
Bases de Datos Genéticas , Genoma , Genómica/métodos , Proteínas/genética , Proteínas/metabolismo , Animales , Composición de Base , Enzimas/genética , Expresión Génica , Internet , Sistemas de Lectura Abierta , Proteínas/clasificación , Análisis de Secuencia/métodos
19.
Nucleic Acids Res ; 29(13): 2884-98, 2001 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-11433035

RESUMEN

High-throughput structural proteomics is expected to generate considerable amounts of data on the progress of structure determination for many proteins. For each protein this includes information about cloning, expression, purification, biophysical characterization and structure determination via NMR spectroscopy or X-ray crystallography. It will be essential to develop specifications and ontologies for standardizing this information to make it amenable to retrospective analysis. To this end we created the SPINE database and analysis system for the Northeast Structural Genomics Consortium. SPINE, which is available at bioinfo.mbb.yale.edu/nesg or nesg.org, is specifically designed to enable distributed scientific collaboration via the Internet. It was designed not just as an information repository but as an active vehicle to standardize proteomics data in a form that would enable systematic data mining. The system features an intuitive user interface for interactive retrieval and modification of expression construct data, query forms designed to track global project progress and external links to many other resources. Currently the database contains experimental data on 985 constructs, of which 740 are drawn from Methanobacterium thermoautotrophicum, 123 from Saccharomyces cerevisiae, 93 from Caenorhabditis elegans and the remainder from other organisms. We developed a comprehensive set of data mining features for each protein, including several related to experimental progress (e.g. expression level, solubility and crystallization) and 42 based on the underlying protein sequence (e.g. amino acid composition, secondary structure and occurrence of low complexity regions). We demonstrate in detail the application of a particular machine learning approach, decision trees, to the tasks of predicting a protein's solubility and propensity to crystallize based on sequence features. We are able to extract a number of key rules from our trees, in particular that soluble proteins tend to have significantly more acidic residues and fewer hydrophobic stretches than insoluble ones. One of the characteristics of proteomics data sets, currently and in the foreseeable future, is their intermediate size ( approximately 500-5000 data points). This creates a number of issues in relation to error estimation. Initially we estimate the overall error in our trees based on standard cross-validation. However, this leaves out a significant fraction of the data in model construction and does not give error estimates on individual rules. Therefore, we present alternative methods to estimate the error in particular rules.


Asunto(s)
Biología Computacional/métodos , Bases de Datos como Asunto , Proteoma/química , Programas Informáticos , Animales , Caenorhabditis elegans/química , Clonación Molecular , Cristalización , Árboles de Decisión , Perfilación de la Expresión Génica , Almacenamiento y Recuperación de la Información , Internet , Methanobacterium/química , Probabilidad , Conformación Proteica , Proteoma/genética , Reproducibilidad de los Resultados , Proyectos de Investigación , Saccharomyces cerevisiae/química , Solubilidad , Interfaz Usuario-Computador
20.
J Nutr Health Aging ; 19(9): 955-60, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26482699

RESUMEN

Health is a multi-dimensional concept, capturing how people feel and function. The broad concept of Active and Healthy Ageing was proposed by the World Health Organisation (WHO) as the process of optimizing opportunities for health to enhance quality of life as people age. It applies to both individuals and population groups. A universal Active and Healthy Ageing definition is not available and it may differ depending on the purpose of the definition and/or the questions raised. While the European Innovation Partnership on Active and Healthy Ageing (EIP on AHA) has had a major impact, a definition of Active and Healthy Ageing is urgently needed. A meeting was organised in Montpellier, France, October 20-21, 2014 as the annual conference of the EIP on AHA Reference Site MACVIA-LR (Contre les Maladies Chroniques pour un Vieillissement Actif en Languedoc Roussillon) to propose an operational definition of Active and Healthy Ageing including tools that may be used for this. The current paper describes the rationale and the process by which the aims of the meeting will be reached.


Asunto(s)
Envejecimiento , Enfermedad Crónica , Salud , Vida Independiente , Calidad de Vida , Ejercicio Físico , Francia , Humanos , Medio Social
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