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1.
Nature ; 609(7925): 41-45, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-36045235

RESUMEN

When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure1-3, and mapping out the strength and the isospin structure (neutron-proton (np) versus proton-proton (pp) pairs) of these virtual excitations is thus critical input for modelling a range of nuclear, particle and astrophysics measurements3-5. Two-nucleon knockout or 'triple coincidence' reactions have been used to measure the relative contribution of np-SRCs and pp-SRCs by knocking out a proton from the SRC and detecting its partner nucleon (proton or neutron). These measurements6-8 have shown that SRCs are almost exclusively np pairs, but they had limited statistics and required large model-dependent final-state interaction corrections. Here we report on measurements using inclusive scattering from the mirror nuclei hydrogen-3 and helium-3 to extract the np/pp ratio of SRCs in systems with a mass number of three. We obtain a measure of the np/pp SRC ratio that is an order of magnitude more precise than previous experiments, and find a marked deviation from the near-total np dominance observed in heavy nuclei. This result implies an unexpected structure in the high-momentum wavefunction for hydrogen-3 and helium-3. Understanding these results will improve our understanding of the short-range part of the nucleon-nucleon interaction.

2.
Phys Rev Lett ; 132(16): 162501, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38701469

RESUMEN

The electromagnetic form factors of the proton and neutron encode information on the spatial structure of their charge and magnetization distributions. While measurements of the proton are relatively straightforward, the lack of a free neutron target makes measurements of the neutron's electromagnetic structure more challenging and more sensitive to experimental or model-dependent uncertainties. Various experiments have attempted to extract the neutron form factors from scattering from the neutron in deuterium, with different techniques providing different, and sometimes large, systematic uncertainties. We present results from a novel measurement of the neutron magnetic form factor using quasielastic scattering from the mirror nuclei ^{3}H and ^{3}He, where the nuclear effects are larger than for deuterium but expected to largely cancel in the cross-section ratios. We extracted values of the neutron magnetic form factor for low-to-modest momentum transfer, 0.6

3.
Phys Rev Lett ; 126(8): 082301, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-33709760

RESUMEN

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2 (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5 GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

4.
Phys Rev Lett ; 125(26): 262501, 2020 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-33449750

RESUMEN

We measure ^{2}H(e,e^{'}p)n cross sections at 4-momentum transfers of Q^{2}=4.5±0.5 (GeV/c)^{2} over a range of neutron recoil momenta p_{r}, reaching up to ∼1.0 GeV/c. We obtain data at fixed neutron recoil angles θ_{nq}=35°, 45°, and 75° with respect to the 3-momentum transfer q[over →]. The new data agree well with previous data, which reached p_{r}∼500 MeV/c. At θ_{nq}=35° and 45°, final state interactions, meson exchange currents, and isobar currents are suppressed and the plane wave impulse approximation provides the dominant cross section contribution. We compare the new data to recent theoretical calculations, where we observe a significant discrepancy for recoil momenta p_{r}>700 MeV/c.

5.
Phys Rev Lett ; 123(2): 022501, 2019 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-31386522

RESUMEN

We present extractions of the nucleon nonsinglet moments utilizing new precision data on the deuteron F_{2} structure function at large Bjorken-x determined via the Rosenbluth separation technique at Jefferson Lab Experimental Hall C. These new data are combined with a complementary set of data on the proton previously measured in Hall C at similar kinematics and world datasets on the proton and deuteron at lower x measured at SLAC and CERN. The new Jefferson Lab data provide coverage of the upper third of the x range, crucial for precision determination of the higher moments. In contrast to previous extractions, these moments have been corrected for nuclear effects in the deuteron using a new global fit to the deuteron and proton data. The obtained experimental moments represent an order of magnitude improvement in precision over previous extractions using high x data. Moreover, recent exciting developments in lattice QCD calculations provide a first ever comparison of these new experimental results with calculations of moments carried out at the physical pion mass, as well as a new approach that first calculates the quark distributions directly before determining moments.

6.
Phys Rev Lett ; 122(2): 022002, 2019 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-30720291

RESUMEN

The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3

7.
Geophys Res Lett ; 46(24): 14826-14835, 2019 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-33012881

RESUMEN

During winter in the mid-latitudes, photochemical oxidation is significantly slower than in summer and the main radical oxidants driving formation of secondary pollutants, such as fine particulate matter and ozone, remain uncertain, owing to a lack of observations in this season. Using airborne observations, we quantify the contribution of various oxidants on a regional basis during winter, enabling improved chemical descriptions of wintertime air pollution transformations. We show that 25-60% of NOx is converted to N2O5 via multiphase reactions between gas-phase nitrogen oxide reservoirs and aerosol particles, with ~93% reacting in the marine boundary layer to form >2.5 ppbv ClNO2. This results in >70% of the oxidizing capacity of polluted air during winter being controlled, not by typical photochemical reactions, but from these multiphase reactions and emissions of volatile organic compounds, such as HCHO, highlighting the control local anthropogenic emissions have on the oxidizing capacity of the polluted wintertime atmosphere.

8.
Indoor Air ; 28(3): 360-372, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29288500

RESUMEN

High-efficiency particulate air (HEPA) filtration in combination with an electrostatic precipitator (ESP) can be a cost-effective approach to reducing indoor particulate exposure, but ESPs produce ozone. The health effect of combined ESP-HEPA filtration has not been examined. We conducted an intervention study in 89 volunteers. At baseline, the air-handling units of offices and residences for all subjects were comprised of coarse, ESP, and HEPA filtration. During the 5-week long intervention, the subjects were split into 2 groups, 1 with just the ESP removed and the other with both the ESP and HEPA removed. Each subject was measured for cardiopulmonary risk indicators once at baseline, twice during the intervention, and once 2 weeks after baseline conditions were restored. Measured indoor and outdoor PM2.5 and ozone concentrations, coupled with time-activity data, were used to calculate exposures. Removal of HEPA filters increased 24-hour mean PM2.5 exposure by 38 (95% CI: 31, 45) µg/m3 . Removal of ESPs decreased 24-hour mean ozone exposure by 2.2 (2.0, 2.5) ppb. No biomarkers were significantly associated with HEPA filter removal. In contrast, ESP removal was associated with a -16.1% (-21.5%, -10.4%) change in plasma-soluble P-selectin and a -3.0% (-5.1%, -0.8%) change in systolic blood pressure, suggesting reduced cardiovascular risks.


Asunto(s)
Filtros de Aire , Contaminación del Aire Interior/análisis , Precipitación Fraccionada/instrumentación , Material Particulado/análisis , Electricidad Estática , Ventilación/instrumentación , Adulto , Contaminación del Aire Interior/efectos adversos , Biomarcadores/sangre , Presión Sanguínea , Femenino , Voluntarios Sanos , Vivienda , Humanos , Masculino , Persona de Mediana Edad , Ozono/efectos adversos , Ozono/análisis , Selectina-P/sangre , Material Particulado/efectos adversos , Ventilación/métodos , Adulto Joven
9.
Ann Oncol ; 28(10): 2377-2385, 2017 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-28945858

RESUMEN

BACKGROUND: Immune checkpoint inhibitor (ICI) monoclonal antibodies (mAbs) targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1) or its ligand (PD-L1) produce unique toxicity profiles. The objective of this review was to identify patterns and incidence of immune-related adverse events (irAE) based on tumour type and ICI class. METHODS: Medline, EMBASE and COCHRANE databases were searched to identify prospective monotherapy trials of ICIs from 2003 to November 2015. Paired reviewers selected studies for inclusion and extracted data. Odds ratio (OR), χ2 tests and multivariable regression models were used to analyse for effect size and associations. RESULTS: We identified 48 trials (6938 patients), including 26 CTLA-4, 17 PD-1, 2 PD-L1 trials, and 3 studies tested both CTLA-4 and PD-1. Grade 3/4 irAE were more common with CTLA-4 mAbs compared with PD-1 (31% versus 10%). All grades colitis (OR 8.7, 95% CI 5.8-12.9), hypophysitis (OR 6.5, 95% CI 3.0-14.3) and rash (OR 2.0, 95% CI 1.8-2.3) were more frequent with CTLA-4 mAbs; whereas pneumonitis (OR 6.4, 95% CI 3.2-12.7), hypothyroidism (OR 4.3, 95% CI 2.9-6.3), arthralgia (OR 3.5, 95% CI 2.6-4.8) and vitiligo (OR 3.5, 95% CI 2.3-5.3) were more common with PD-1 mAbs. Comparison of irAE from the three most studied tumour types in PD-1 mAbs trials [melanoma (n = 2048), non-small-cell lung cancer (n = 1030) and renal cell carcinoma (n = 573)] showed melanoma patients had a higher frequency of gastrointestinal and skin irAE and lower frequency of pneumonitis. DISCUSSION: CTLA-4 and PD-1 mAbs have distinct irAE profiles. Different immune microenvironments may drive histology-specific irAE patterns. Other tumour-dependent irAE profiles may be identified as data emerge from ICI trials.


Asunto(s)
Anticuerpos Monoclonales/efectos adversos , Antineoplásicos Inmunológicos/efectos adversos , Antígeno CTLA-4/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/inmunología , Antineoplásicos Inmunológicos/administración & dosificación , Antineoplásicos Inmunológicos/inmunología , Antígeno CTLA-4/inmunología , Ensayos Clínicos como Asunto/métodos , Humanos , Enfermedades del Sistema Inmune/inducido químicamente , Enfermedades del Sistema Inmune/inmunología , Neoplasias/inmunología , Receptor de Muerte Celular Programada 1/inmunología , Ensayos Clínicos Controlados Aleatorios como Asunto/métodos
10.
J Evol Biol ; 30(12): 2255, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-29105876

RESUMEN

Based on negative data, Douglas et al refuted earlier work by the O'Day laboratory on the role of pheromones in the sexual development of Dictyostelium discoideum. This letter addresses some of the issues with their study.


Asunto(s)
Amoeba , Dictyostelium , Feromonas , Reproducción , Desarrollo Sexual
11.
J Vet Pharmacol Ther ; 40(4): 363-369, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27885695

RESUMEN

The pharmacokinetics of intramuscularly administered ceftiofur crystalline-free acid (CCFA) were determined in pigs that were clinically healthy (n = 8), vaccinated with a Porcine reproductive and respiratory syndrome modified live virus (PRRS MLV) (n = 10), challenged with wild-type porcine reproductive and respiratory syndrome virus (PRRSv) VR-2385 (n = 10), or vaccinated with PRRS MLV and later challenged with wild-type PRRSv VR-2385 (n = 10). Animals were given a single dose of CCFA intramuscularly at 5 mg/kg body weight. Blood was collected at 0 (pretreatment), 0.25, 0.5, 1, 6, 12, 24, 48, 96, 144, 192, and 240 h postinjection. Plasma was analyzed using liquid chromatography-mass spectrometry. Plasma concentration-time curves for each group were evaluated with noncompartmental modeling. When compared to control animals, those receiving the PRRSv wild-type challenge only had a lower AUC0-last , higher Cl/F, and higher Vz/F. The PRRSv wild-type challenge only group had the longest T1/2λ . The Cmax did not differ among all four treatments. Control animals had no statistically significant differences from animals vaccinated with PRRS MLV alone or animals vaccinated with PRRS MLV and later challenged with wild-type PRRSv. Our results suggest that PRRSv wild-type infection has the potential to alter CCFA pharmacokinetics and PRRS MLV vaccination may attenuate those changes.


Asunto(s)
Cefalosporinas/farmacocinética , Síndrome Respiratorio y de la Reproducción Porcina/inmunología , Enfermedades de los Porcinos/prevención & control , Vacunación/veterinaria , Animales , Inyecciones Intramusculares/veterinaria , Virus del Síndrome Respiratorio y Reproductivo Porcino , Porcinos
12.
J Med Genet ; 52(8): 514-22, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26092869

RESUMEN

BACKGROUND: Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterised by hypotonia, ataxia, cognitive impairment, abnormal eye movements, respiratory control disturbances and a distinctive mid-hindbrain malformation. JS demonstrates substantial phenotypic variability and genetic heterogeneity. This study provides a comprehensive view of the current genetic basis, phenotypic range and gene-phenotype associations in JS. METHODS: We sequenced 27 JS-associated genes in 440 affected individuals (375 families) from a cohort of 532 individuals (440 families) with JS, using molecular inversion probe-based targeted capture and next-generation sequencing. Variant pathogenicity was defined using the Combined Annotation Dependent Depletion algorithm with an optimised score cut-off. RESULTS: We identified presumed causal variants in 62% of pedigrees, including the first B9D2 mutations associated with JS. 253 different mutations in 23 genes highlight the extreme genetic heterogeneity of JS. Phenotypic analysis revealed that only 34% of individuals have a 'pure JS' phenotype. Retinal disease is present in 30% of individuals, renal disease in 25%, coloboma in 17%, polydactyly in 15%, liver fibrosis in 14% and encephalocele in 8%. Loss of CEP290 function is associated with retinal dystrophy, while loss of TMEM67 function is associated with liver fibrosis and coloboma, but we observe no clear-cut distinction between JS subtypes. CONCLUSIONS: This work illustrates how combining advanced sequencing techniques with phenotypic data addresses extreme genetic heterogeneity to provide diagnostic and carrier testing, guide medical monitoring for progressive complications, facilitate interpretation of genome-wide sequencing results in individuals with a variety of phenotypes and enable gene-specific treatments in the future.


Asunto(s)
Cerebelo/anomalías , Heterogeneidad Genética , Retina/anomalías , Anomalías Múltiples/genética , Anomalías Múltiples/patología , Cerebelo/patología , Estudios de Cohortes , Análisis Mutacional de ADN , Anomalías del Ojo/genética , Anomalías del Ojo/patología , Estudios de Asociación Genética , Humanos , Enfermedades Renales Quísticas/genética , Enfermedades Renales Quísticas/patología , Modelos Teóricos , Linaje , Retina/patología , Análisis de Secuencia de ADN
13.
Intern Med J ; 46(11): 1291-1297, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27507629

RESUMEN

BACKGROUND: The role of cytoreductive nephrectomy (CN) for metastatic renal cell carcinoma (mRCC) in the era of targeted therapies is currently undefined. In recent years, neutrophil-to-lymphocyte ratio (NLR) has emerged as a prognostic marker in several cancers, including mRCC. In this multicentre retrospective study, we aim to assess the impact of CN in mRCC and the value of NLR in risk stratification and patient selection. METHODS: Retrospective data from patients with de novo mRCC from four large Australian hospitals were collected. Survival analyses were performed using the Kaplan-Meier method and compared using the log-rank test. Multivariate analyses were performed using the Cox proportional hazards method. RESULTS: Our study identified 91 de novo mRCC patients. Patients who underwent CN (n = 46, 51%) were more likely to be younger (59.0 years vs 64.6 years, P = 0.019) and to have received systemic therapy (91% vs 76%, P = 0.043). Median overall survival (mOS) was significantly improved in patients who underwent CN (23.0 months vs 10.9 months, hazard ratios (HR) 0.33, 95% confidence interval (CI) 0.20-0.55, P < 0.0001). Patients with NLR ≥ 5 also had inferior mOS (6.2 months vs 16.7 months, HR 1.94, 95% CI 1.14-3.29, P = 0.014). CN was associated with substantially improved survival in patients with both NLR < 5 (mOS 31.1 months vs 7.0 months, HR 0.41, 95% CI, 0.18-0.64, P = 0.0009) and NLR ≥ 5 (mOS 10.9 months vs 2.3 months, HR 0.33, 95% CI, 0.11-0.69, P = 0.009). Significant survival benefits associated with CN were maintained in multivariate analyses (HR 0.39, 95% CI 0.22-0.70, P = 0.0014). CONCLUSIONS: CN is associated with significantly improved overall survival in de novo mRCC. The incremental survival benefit associated with CN was seen irrespective of NLR.


Asunto(s)
Carcinoma de Células Renales/cirugía , Procedimientos Quirúrgicos de Citorreducción , Neoplasias Renales/cirugía , Nefrectomía , Australia/epidemiología , Carcinoma de Células Renales/mortalidad , Femenino , Humanos , Neoplasias Renales/mortalidad , Linfocitos/citología , Masculino , Persona de Mediana Edad , Análisis Multivariante , Neutrófilos/citología , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento
14.
Phys Rev Lett ; 115(15): 152001, 2015 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-26550716

RESUMEN

Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The wide-angle Compton scattering polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of θ_{cm}^{p}=70°. The longitudinal transfer K_{LL}, measured to be 0.645±0.059±0.048, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is ~3 times larger than predicted by the generalized-parton-distribution-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

15.
Int J Clin Pract ; 69(6): 659-65, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25648886

RESUMEN

AIMS: The objective of this study is to externally validate the SOAR stroke score (Stroke subtype, Oxfordshire Community Stroke Project Classification, Age and prestroke modified Rankin score) in predicting hospital length of stay (LOS) following an admission for acute stroke. METHODS: We conducted a multi-centre observational study in eight National Health Service hospital trusts in the Anglia Stroke & Heart Clinical Network between September 2008 and April 2011. The usefulness of the SOAR stroke score in predicting hospital LOS in the acute settings was examined for all stroke and then stratified by discharge status (discharged alive or died during the admission). RESULTS: A total of 3596 patients (mean age 77 years) with first-ever or recurrent stroke (92% ischaemic) were included. Increasing LOS was observed with increasing SOAR stroke score (p < 0.001 for both mean and median) and the SOAR stroke score of 0 had the shortest mean LOS (12 ± 20 days) while the SOAR stroke score of 6 had the longest mean LOS (26 ± 28 days). Among patients who were discharged alive, increasing SOAR stroke score had a significantly higher mean and median LOS (p < 0.001 for both mean and median) and the LOS peaked among patients with score value of 6 [mean (SD) 35 ± 31 days, median (IQR) 23 (14-48) days]. For patients who died as in-patient, there was no significant difference in mean or median LOS with increasing SOAR stroke score (p = 0.68 and p = 0.79, respectively). CONCLUSION: This external validation study confirms the usefulness of the SOAR stroke score in predicting LOS in patients with acute stroke especially in those who are likely to survive to discharge. This provides a simple prognostic score useful for clinicians, patients and service providers.


Asunto(s)
Tiempo de Internación/estadística & datos numéricos , Evaluación de Resultado en la Atención de Salud/métodos , Índice de Severidad de la Enfermedad , Accidente Cerebrovascular , Enfermedad Aguda , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Accidente Cerebrovascular/mortalidad
16.
J Vet Pharmacol Ther ; 38(5): 475-81, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25689130

RESUMEN

This study determined the impact of porcine reproductive and respiratory syndrome virus (PRRSV) and Streptococcus suis coinfection on the pharmacokinetic (PK) profile of ceftiofur hydrochloride in pigs after intramuscular (i.m.) injection. Eighteen clinically normal crossbred gilts were assigned by weight into a challenge group (10 pigs) and control group (eight pigs). Pigs in both groups received a single i.m. injection of ceftiofur hydrochloride (Excenel RTU Sterile Suspension; Zoetis) at a 5 mg/kg BW dose. Serial blood samples were collected to characterize the plasma concentration curve. After a 10 days drug washout period, the challenge group was inoculated with 2 mL of PRRSV isolate VR-2385 (10(5.75) 50% tissue culture infective doses per mL) intranasally and 8 days later inoculated S. suis. When clinical disease was evident, the second PK assessment began in both challenge and control groups. Coinfected pigs demonstrated lower values of AUC and CMAX , but higher values of Cl/F and Vz/F indicating drug kinetics were altered by infection. The data from this study have implications on ceftiofur treatment regimens in diseased pigs.


Asunto(s)
Antibacterianos/farmacocinética , Cefalosporinas/farmacocinética , Coinfección/veterinaria , Síndrome Respiratorio y de la Reproducción Porcina/tratamiento farmacológico , Virus del Síndrome Respiratorio y Reproductivo Porcino , Infecciones Estreptocócicas/veterinaria , Streptococcus suis , Enfermedades de los Porcinos/tratamiento farmacológico , Animales , Antibacterianos/uso terapéutico , Cefalosporinas/uso terapéutico , Coinfección/tratamiento farmacológico , Coinfección/metabolismo , Coinfección/microbiología , Coinfección/virología , Femenino , Inyecciones Intramusculares/veterinaria , Síndrome Respiratorio y de la Reproducción Porcina/metabolismo , Síndrome Respiratorio y de la Reproducción Porcina/microbiología , Infecciones Estreptocócicas/complicaciones , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/microbiología , Infecciones Estreptocócicas/virología , Porcinos/metabolismo , Porcinos/microbiología , Porcinos/virología , Enfermedades de los Porcinos/microbiología , Enfermedades de los Porcinos/virología
17.
Phys Rev Lett ; 113(2): 022501, 2014 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-25062168

RESUMEN

We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.

18.
Opt Lett ; 38(20): 4204-7, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-24321960

RESUMEN

We present a gas jet array for use in high-order harmonic generation experiments. Precise control of the pressure in each individual gas jet has allowed a thorough investigation into mechanisms contributing to the selective enhancement observed in the harmonic spectra produced by dual-gas, multi-jet arrays. Our results reveal that in our case, the dominant enhancement mechanism is the result of a compression of the harmonic-producing gas jet due to the presence of other gas jets in the array. The individual control of the gas jets in the array also provides a promising method for enhancing the harmonic yield by precise tailoring of the length and pressure gradient of the interaction region.

19.
Environ Sci Technol ; 47(21): 12566-74, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24088179

RESUMEN

Airborne measurements of aerosol composition and gas phase compounds over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico in June 2010 indicated the presence of high concentrations of secondary organic aerosol (SOA) formed from organic compounds of intermediate volatility. In this work, we investigated SOA formation from South Louisiana crude oil vapors reacting with OH in a Potential Aerosol Mass flow reactor. We use the dependence of evaporation time on the saturation concentration (C*) of the SOA precursors to separate the contribution of species of different C* to total SOA formation. This study shows consistent results with those at the DWH oil spill: (1) organic compounds of intermediate volatility with C* = 10(5)-10(6) µg m(-3) contribute the large majority of SOA mass formed, and have much larger SOA yields (0.37 for C* = 10(5) and 0.21 for C* = 10(6) µg m(-3)) than more volatile compounds with C*≥10(7) µg m(-3), (2) the mass spectral signature of SOA formed from oxidation of the less volatile compounds in the reactor shows good agreement with that of SOA formed at DWH oil spill. These results also support the use of flow reactors simulating atmospheric SOA formation and aging.


Asunto(s)
Aerosoles/química , Contaminantes Atmosféricos/química , Petróleo/análisis , Gases , Golfo de México , Laboratorios , Compuestos Orgánicos/análisis , Contaminación por Petróleo , Volatilización
20.
ESMO Open ; 8(4): 101586, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-37356359

RESUMEN

INTRODUCTION: Next-generation sequencing (NGS) diagnostics have shown clinical utility in predicting survival benefits in patients with certain cancer types who are undergoing targeted drug therapies. Currently, there are no guidelines or recommendations for the use of NGS in patients with metastatic cancer from an Asian perspective. In this article, we present the Asia-Pacific Oncology Drug Development Consortium (APODDC) recommendations for the clinical use of NGS in metastatic cancers. METHODS: The APODDC set up a group of experts in the field of clinical cancer genomics to (i) understand the current NGS landscape for metastatic cancers in the Asia-Pacific (APAC) region; (ii) discuss key challenges in the adoption of NGS testing in clinical practice; and (iii) adapt/modify the European Society for Medical Oncology guidelines for local use. Nine cancer types [breast cancer (BC), gastric cancer (GC), nasopharyngeal cancer (NPC), ovarian cancer (OC), prostate cancer, lung cancer, and colorectal cancer (CRC) as well as cholangiocarcinoma and hepatocellular carcinoma (HCC)] were identified, and the applicability of NGS was evaluated in daily practice and/or clinical research. Asian ethnicity, accessibility of NGS testing, reimbursement, and socioeconomic and local practice characteristics were taken into consideration. RESULTS: The APODDC recommends NGS testing in metastatic non-small-cell lung cancer (NSCLC). Routine NGS testing is not recommended in metastatic BC, GC, and NPC as well as cholangiocarcinoma and HCC. The group suggested that patients with epithelial OC may be offered germline and/or somatic genetic testing for BReast CAncer gene 1 (BRCA1), BRCA2, and other OC susceptibility genes. Access to poly (ADP-ribose) polymerase inhibitors is required for NGS to be of clinical utility in prostate cancer. Allele-specific PCR or a small-panel multiplex-gene NGS was suggested to identify key alterations in CRC. CONCLUSION: This document offers practical guidance on the clinical utility of NGS in specific cancer indications from an Asian perspective.


Asunto(s)
Neoplasias de la Mama , Carcinoma Hepatocelular , Carcinoma de Pulmón de Células no Pequeñas , Colangiocarcinoma , Neoplasias Hepáticas , Neoplasias Pulmonares , Neoplasias Nasofaríngeas , Neoplasias Ováricas , Neoplasias de la Próstata , Masculino , Femenino , Humanos , Carcinoma de Pulmón de Células no Pequeñas/genética , Neoplasias Pulmonares/genética , Neoplasias Ováricas/genética , Neoplasias de la Mama/genética , Oncología Médica , Secuenciación de Nucleótidos de Alto Rendimiento
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