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3.
Phys Rev Lett ; 119(16): 162501, 2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-29099223

RESUMO

The charge and magnetic form factors, F_{C} and F_{M}, respectively, of ^{3}He are extracted in the kinematic range 25 fm^{-2}≤Q^{2}≤61 fm^{-2} from elastic electron scattering by detecting ^{3}He recoil nuclei and scattered electrons in coincidence with the two High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements find evidence for the existence of a second diffraction minimum for the magnetic form factor at Q^{2}=49.3 fm^{-2} and for the charge form factor at Q^{2}=62.0 fm^{-2}. Both minima are predicted to exist in the Q^{2} range accessible by this Jefferson Lab experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem.

5.
Phys Rev Lett ; 112(13): 132503, 2014 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-24745410

RESUMO

The charge form factor of 4He has been extracted in the range 29 fm(-2) ≤ Q2 ≤ 77 fm(-2) from elastic electron scattering, detecting 4He recoil nuclei and electrons in coincidence with the high resolution spectrometers of the Hall A Facility of Jefferson Lab. The measurements have uncovered a second diffraction minimum for the form factor, which was predicted in the Q2 range of this experiment. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the few-body problem.

6.
Phys Rev Lett ; 108(7): 072301, 2012 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-22401196

RESUMO

We report new STAR measurements of midrapidity yields for the Λ, Λ[over ¯], K(S)(0), Ξ(-), Ξ[over ¯](+), Ω(-), Ω[over ¯](+) particles in Cu+Cu collisions at √S(NN)==200 GeV, and midrapidity yields for the Λ, Λ[over ¯], K(S)(0) particles in Au+Au at √S(NN)==200 GeV. We show that, at a given number of participating nucleons, the production of strange hadrons is higher in Cu+Cu collisions than in Au+Au collisions at the same center-of-mass energy. We find that aspects of the enhancement factors for all particles can be described by a parametrization based on the fraction of participants that undergo multiple collisions.

7.
Phys Rev Lett ; 108(7): 072302, 2012 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-22401197

RESUMO

We report transverse momentum (p(T)≤15 GeV/c) spectra of π(±), K(±), p, p[over ¯], K(S)(0), and ρ(0) at midrapidity in p+p and Au+Au collisions at √S(NN)=200 GeV. Perturbative QCD calculations are consistent with π(±) spectra in p+p collisions but do not reproduce K and p(p[over ¯]) spectra. The observed decreasing antiparticle-to-particle ratios with increasing p(T) provide experimental evidence for varying quark and gluon jet contributions to high-p(T) hadron yields. The relative hadron abundances in Au+Au at p(T)≳8 GeV/c are measured to be similar to the p+p results, despite the expected Casimir effect for parton energy loss.

8.
Phys Rev Lett ; 108(20): 202301, 2012 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-23003142

RESUMO

STAR's measurements of directed flow (v1) around midrapidity for π±, K±, KS0, p, and p[over ¯] in Au+Au collisions at √[sNN]=200 GeV are presented. A negative v1(y) slope is observed for most of produced particles (π±, K±, KS0, and p[over ¯]). In 5%-30% central collisions, a sizable difference is present between the v1(y) slope of protons and antiprotons, with the former being consistent with zero within errors. The v1 excitation function is presented. Comparisons to model calculations (RQMD, UrQMD, AMPT, QGSM with parton recombination, and a hydrodynamics model with a tilted source) are made. For those models which have calculations of v1 for both pions and protons, none of them can describe v1(y) for pions and protons simultaneously. The hydrodynamics model with a tilted source as currently implemented cannot explain the centrality dependence of the difference between the v1(y) slopes of protons and antiprotons.

9.
Phys Rev Lett ; 106(6): 062002, 2011 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-21405460

RESUMO

We report the first measurement of the parity-violating single-spin asymmetries for midrapidity decay positrons and electrons from W+ and W- boson production in longitudinally polarized proton-proton collisions at sqrt[s] = 500 GeV by the STAR experiment at RHIC. The measured asymmetries, A(L)(W+) = -0.27 ± 0.10(stat.) ± 0.02(syst.) ± 0.03(norm.) and A(L)(W-) = 0.14 ± 0.19(stat.) ± 0.02(syst.) ± 0.01(norm.), are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized deep-inelastic scattering measurements.

10.
Phys Rev Lett ; 105(20): 202301, 2010 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-21231222

RESUMO

The contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at √s=200 GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of pT≥5 GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high pT.

11.
Phys Rev Lett ; 105(2): 022301, 2010 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-20867701

RESUMO

We report the first three-particle coincidence measurement in pseudorapidity (Δη) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |Δϕ|<0.7 in square root of s(NN)=200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range Δη correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured Δη. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

12.
Phys Rev Lett ; 105(2): 022302, 2010 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-20867702

RESUMO

We report the first measurements of the kurtosis (κ), skewness (S), and variance (σ2) of net-proton multiplicity (Np-Np) distributions at midrapidity for Au+Au collisions at square root of s(NN)=19.6, 62.4, and 200 GeV corresponding to baryon chemical potentials (µB) between 200 and 20 MeV. Our measurements of the products κσ2 and Sσ, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the square root of s(NN) dependence of κσ2. From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for µB below 200 MeV.

13.
Phys Rev Lett ; 103(25): 251601, 2009 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-20366248

RESUMO

Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system's orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au + Au and Cu + Cu collisions at square root of s(NN) = 200 GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation.

14.
Phys Rev Lett ; 103(17): 172301, 2009 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-19905749

RESUMO

Forward-backward multiplicity correlation strengths have been measured with the STAR detector for Au + Au and p + p collisions at square root of s(NN) = 200 GeV. Strong short- and long-range correlations (LRC) are seen in central Au + Au collisions. The magnitude of these correlations decrease with decreasing centrality until only short-range correlations are observed in peripheral Au + Au collisions. Both the dual parton model (DPM) and the color glass condensate (CGC) predict the existence of the long-range correlations. In the DPM, the fluctuation in the number of elementary (parton) inelastic collisions produces the LRC. In the CGC, longitudinal color flux tubes generate the LRC. The data are in qualitative agreement with the predictions of the DPM and indicate the presence of multiple parton interactions.

15.
Zoonoses Public Health ; 65(1): e265-e269, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29265702

RESUMO

During the last 10 years, scientists have grown increasingly aware that emerging respiratory viruses are often zoonotic in their origin. These infections can originate from or be amplified in livestock. Less commonly recognized are instances when humans have transmitted their respiratory pathogens to animals (reverse zoonoses). Even with this knowledge of viral exchange at the human-livestock interface, few studies have been conducted to understand this cross-over. In this pilot study, we examined persons with influenza-like illness at an outpatient clinic for evidence of infection with novel zoonotic respiratory pathogens in rural North Carolina where there are dense swine and poultry farming. Environmental air sampling was also conducted. From July 2016 to March 2017, a total of 14 human subjects were enrolled and sampled, and 192 bioaerosol samples were collected. Of the 14 human subject samples molecularly tested, three (21.4%) were positive for influenza A, one (7.1%) for influenza B and one (7.1%) for human enterovirus. Of the 192 bioaerosol samples collected and tested by real-time RT-PCR or PCR, three (1.6%) were positive for influenza A and two (1.0%) for adenovirus. No evidence was found for novel zoonotic respiratory viruses.


Assuntos
Enterovirus Humano A/isolamento & purificação , Infecções por Enterovirus/virologia , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/virologia , Infecções Respiratórias/virologia , Adolescente , Adulto , Aerossóis , Criança , Pré-Escolar , Infecções por Enterovirus/epidemiologia , Feminino , Humanos , Lactente , Influenza Humana/epidemiologia , Masculino , North Carolina/epidemiologia , Projetos Piloto , Vigilância da População , Infecções Respiratórias/epidemiologia , População Rural , Adulto Jovem
16.
Cancer Gene Ther ; 13(8): 732-8, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16543921

RESUMO

Because of their ability to replicate, the dose-response relationships of oncolytic viruses cannot easily be predicted. To better understand the pharmacokinetics of virotherapy in relation to viral dose and schedule, we administered MV-CEA intraperitoneally in an orthotopic mouse model of ovarian cancer. MV-CEA is an attenuated oncolytic measles virus engineered to express soluble human carcinoembryonic antigen (CEA), and the virus is currently undergoing phase I clinical testing in patients with ovarian cancer. Plasma CEA levels correlate with numbers of virus-infected tumor cells at a given time, and were used as a surrogate to monitor the profiles of viral gene expression over time. The antineoplastic activity of single- or multiple-dose MV-CEA was apparent over a wide range of virus doses (10(3)-10(8) TCID(50)), with little reduction in observed antitumor efficacy, even at the lowest tested dose. However, analysis of CEA profiles of treated mice was highly informative, illustrating the variability in virus kinetics at different dose levels. The highest doses of virus were associated with higher initial levels of tumor cell killing, but the final outcome of MV-CEA therapy at all dose levels was a partial equilibrium between virus and tumor, resulting in significant slowing of tumor growth and enhanced survival of the mice.


Assuntos
Vírus do Sarampo , Terapia Viral Oncolítica , Neoplasias Ovarianas/terapia , Animais , Antígeno Carcinoembrionário/biossíntese , Antígeno Carcinoembrionário/sangue , Relação Dose-Resposta Imunológica , Feminino , Humanos , Camundongos , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/patologia , Carga Tumoral , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
17.
Biochim Biophys Acta ; 1370(1): 64-76, 1998 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-9518554

RESUMO

The effects of changes in bilayer phase structure on the permeability of acetic acid and trimethylacetic acid were studied in large unilamellar vesicles (LUVs) composed of dipalmitoylphosphatidylcholine (DPPC)/cholesterol (CHOL), dihexadecylphosphatidylcholine (DHPC)/CHOL, or DPPC/dimyristoylphosphatidylcholine (DMPC) using an NMR line-broadening method. Phase transitions were induced by changes in temperature and lipid composition (i.e., XCHOL was varied from 0.0 to 0.5 and XDMPC from 0.0 to 1.0). In DPPC/CHOL and DHPC/CHOL bilayers, the addition of CHOL induces only a modest change in the permeability coefficient (Pm) of acetic acid in the gel-phase (Pbeta') but significantly reduces Pm in ordered and disordered liquid-crystalline phases (Lo and Lalpha). Abrupt changes in slopes in semi-logarithmic plots of Pm vs. XCHOL occur at specific values of XCHOL and temperature corresponding to the boundaries between Pbeta' and Lo or between Lalpha and Lo phases. In most respects, phase diagrams generated from the break points in plots of Pm vs. XCHOL obtained at various temperatures in DHPC/CHOL and DPPC/CHOL bilayers closely resemble those constructed previously for DPPC/CHOL bilayers using NMR and DSC methods. Above Tm, the phase diagrams generated from permeability data reveal the presence of both the disordered (Lalpha) and the ordered (Lo) liquid-crystalline phases, as well as the two-phase coexistence region. In DPPC/DMPC bilayers, the addition of DMPC increases Pm dramatically in the gel phase but only slightly in the liquid-crystalline phase. Abrupt changes in slopes in semi-logarithmic plots of Pm vs. XDMPC also occur at specific values of XDMPC and temperature, from which a phase diagram can be constructed which closely resembles diagrams obtained previously by other methods. These correlations indicate that trans-bilayer permeability measurements can be used to construct lipid bilayer phase diagrams. Positive deviations of Pm from predicted values based on the phase lever rule are observed in the two-phase coexistence regions with the degree of the deviation depending on bilayer chemical composition and temperature. These results may reflect a specific contribution of the interfacial region between two phases to higher solute permeability or may be due to the higher lateral compressibility of lipid bilayers in the two-phase coexistence region.


Assuntos
Bicamadas Lipídicas/química , 1,2-Dipalmitoilfosfatidilcolina/química , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , Dimiristoilfosfatidilcolina/química , Dimiristoilfosfatidilcolina/metabolismo , Luz , Bicamadas Lipídicas/metabolismo , Lipossomos/química , Lipossomos/metabolismo , Espectroscopia de Ressonância Magnética , Permeabilidade , Éteres Fosfolipídicos/química , Éteres Fosfolipídicos/metabolismo , Espalhamento de Radiação , Temperatura
18.
J Invest Dermatol ; 93(2): 280-6, 1989 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-2754277

RESUMO

The permeability coefficients (kp) of a series of methyl-substituted p-cresols were determined in human stratum corneum along with their partition coefficients (PC) between water and untreated stratum corneum, delipidized stratum corneum, octanol, and heptane. The PC values were identical in untreated and delipidized stratum corneum, suggesting that the stratum corneum/water PC data reflect the protein domain rather than the lipids. Although uptake into human stratum corneum was relatively insensitive to solute lipophilicity, reflecting the predominant role of proteins in the uptake, permeability coefficients were found to be more sensitive to lipophilicity, suggesting that transport is by a lipid pathway. A log-log plot of kp versus stratum corneum/water PC within the phenol series is linear, but with a slope of 3.6, indicating that kp is not directly proportional to PC. Functional group contributions to the free energy of the transfer process reflected in permeability or partitioning experiments were compared with group contribution data generated previously for the same substituents attached to the chain terminus of 21-esters of hydrocortisone. Within experimental error, a given functional group altered permeability by the same factor in either series of compounds. Group contributions of polar, hydrogen bonding substituents obtained from kp data were similar to those from octanol/water PC data, suggesting that the barrier microenvironment resembles that of a hydrogen bonding organic solvent. Comparison of the kp values of substituted p-cresols with those of hydrocortisone esters having similar lipophilicities also indicated a steep dependence of kp on molecular weight (log kp = constant + psi log PC - n log MW, n = 4.6) similar to the dependence observed in other biomembranes and isolated lipid bilayers.


Assuntos
Cresóis/farmacocinética , Pele/metabolismo , Fenômenos Químicos , Química , Humanos , Modelos Biológicos , Peso Molecular , Permeabilidade
19.
J Med Chem ; 35(13): 2347-54, 1992 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-1619614

RESUMO

A series of isomeric 2',3'-dideoxynucleosides which contains a modified carbohydrate moiety has been prepared. This class of compounds was designed to mimic the activity of known anti-HIV dideoxynucleosides, while imparting enhanced chemical and enzymatic stability. Isonucleosides containing the standard heterocyclic bases (A, C, G, T) were synthesized via nucleophilic addition of the base to an isomeric sugar unit. Modified derivatives were generated by manipulation of the intact isonucleoside. Two of the compound prepared, iso-ddA (1) and iso-ddG (6), exhibit significant and selective anti-HIV activity, as well as beneficial hydrolytic stability.


Assuntos
Antivirais/síntese química , Didesoxinucleosídeos/síntese química , HIV-1 , Antivirais/farmacologia , Células Cultivadas , Cromatografia Líquida , Didesoxinucleosídeos/farmacologia , Estabilidade de Medicamentos , Produtos do Gene gag/biossíntese , HIV-1/fisiologia , Humanos , Isomerismo , Monócitos/metabolismo , Análise Espectral , Replicação Viral/efeitos dos fármacos
20.
Antiviral Res ; 25(3-4): 245-58, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7710271

RESUMO

We attempted to detect drug-related HIV-1 pol gene mutations by selective polymerase chain reaction (PCR) using both proviral DNA and viral RNA isolated from patients (pts) with AIDS or ARC receiving antiretroviral therapy. Peripheral blood mononuclear cell (PBM)-associated proviral DNA and serum-derived viral RNA were obtained from eight patients before and after receiving an alternating regimen of AZT and ddC for 15-41 months or ddI monotherapy for 12-26 months. These specimens were examined for the presence of mutations at positions 70, 74, 215 and 219. We noted that selective PCR results can be ambiguous depending on the quantity of DNA template employed. We, therefore, used the minimal quantity of DNA templates that yielded evaluable PCR products in this study. For all the eight pairs of pre- and post-therapy proviral DNA samples, selective PCR results agreed with independently determined nucleotide sequences. Results of reverse transcription of serum-derived viral RNA followed by selective PCR differed in some cases from those using the proviral DNA. In particular, the use of serum viral RNA appeared to allow earlier detection of changes in drug-related mutations than the use of PBM-associated proviral DNA. We conclude that (i) selective PCR using the minimum and sufficient number of PBM-associated proviral DNA and serum viral RNA copies successfully detects the presence of known pol gene mutations; (ii) drug-related mutations may be distinguished earlier in virions in serum (or plasma) than in proviral DNA in PBM; and (iii) quantification of HIV-1 prior to selective PCR may be an important component in monitoring the therapy of HIV-1 infection.


Assuntos
Antivirais/farmacologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/genética , Mutação , Reação em Cadeia da Polimerase/métodos , Sequência de Bases , Primers do DNA , DNA Viral/sangue , DNA Viral/genética , Didanosina/farmacologia , Eficiência , Estudos de Avaliação como Assunto , Genes pol/efeitos dos fármacos , Genes pol/genética , Genótipo , Infecções por HIV/tratamento farmacológico , Humanos , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/virologia , Dados de Sequência Molecular , Provírus/genética , RNA Viral/sangue , RNA Viral/genética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Moldes Genéticos , Vírion/genética , Zalcitabina/farmacologia , Zidovudina/farmacologia
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