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1.
Nature ; 615(7954): 813-816, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36991189

RESUMO

The proton is one of the main building blocks of all visible matter in the Universe1. Among its intrinsic properties are its electric charge, mass and spin2. These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering2. An example is the highly precise measurement of the electric charge radius of the proton6. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton7,8 from our measurement. We used a variety of models9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics12. This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

2.
Nature ; 611(7935): 265-270, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36261531

RESUMO

The visible world is founded on the proton, the only composite building block of matter that is stable in nature. Consequently, understanding the formation of matter relies on explaining the dynamics and the properties of the proton's bound state. A fundamental property of the proton involves the response of the system to an external electromagnetic field. It is characterized by the electromagnetic polarizabilities1 that describe how easily the charge and magnetization distributions inside the system are distorted by the electromagnetic field. Moreover, the generalized polarizabilities2 map out the resulting deformation of the densities in a proton subject to an electromagnetic field. They disclose essential information about the underlying system dynamics and provide a key for decoding the proton structure in terms of the theory of the strong interaction that binds its elementary quark and gluon constituents. Of particular interest is a puzzle in the electric generalized polarizability of the proton that remains unresolved for two decades2. Here we report measurements of the proton's electromagnetic generalized polarizabilities at low four-momentum transfer squared. We show evidence of an anomaly to the behaviour of the proton's electric generalized polarizability that contradicts the predictions of nuclear theory and derive its signature in the spatial distribution of the induced polarization in the proton. The reported measurements suggest the presence of a new, not-yet-understood dynamical mechanism in the proton and present notable challenges to the nuclear theory.

3.
Phys Rev Lett ; 128(13): 132003, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35426713

RESUMO

The ratio of the nucleon F_{2} structure functions, F_{2}^{n}/F_{2}^{p}, is determined by the MARATHON experiment from measurements of deep inelastic scattering of electrons from ^{3}H and ^{3}He nuclei. The experiment was performed in the Hall A Facility of Jefferson Lab using two high-resolution spectrometers for electron detection, and a cryogenic target system which included a low-activity tritium cell. The data analysis used a novel technique exploiting the mirror symmetry of the two nuclei, which essentially eliminates many theoretical uncertainties in the extraction of the ratio. The results, which cover the Bjorken scaling variable range 0.19

4.
Phys Rev Lett ; 126(8): 082301, 2021 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-33709760

RESUMO

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.

5.
Phys Rev Lett ; 125(26): 262501, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33449750

RESUMO

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.

6.
Phys Rev Lett ; 124(21): 212501, 2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32530643

RESUMO

We report the first measurement of the (e,e^{'}p) three-body breakup reaction cross sections in helium-3 (^{3}He) and tritium (^{3}H) at large momentum transfer [⟨Q^{2}⟩≈1.9 (GeV/c)^{2}] and x_{B}>1 kinematics, where the cross section should be sensitive to quasielastic (QE) scattering from single nucleons. The data cover missing momenta 40≤p_{miss}≤500 MeV/c that, in the QE limit with no rescattering, equals the initial momentum of the probed nucleon. The measured cross sections are compared with state-of-the-art ab initio calculations. Overall good agreement, within ±20%, is observed between data and calculations for the full p_{miss} range for ^{3}H and for 100≤p_{miss}≤350 MeV/c for ^{3}He. Including the effects of rescattering of the outgoing nucleon improves agreement with the data at p_{miss}>250 MeV/c and suggests contributions from charge-exchange (SCX) rescattering. The isoscalar sum of ^{3}He plus ^{3}H, which is largely insensitive to SCX, is described by calculations to within the accuracy of the data over the entire p_{miss} range. This validates current models of the ground state of the three-nucleon system up to very high initial nucleon momenta of 500 MeV/c.

7.
Phys Rev Lett ; 122(16): 162301, 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31075002

RESUMO

First measurements of double-polarization observables in ω photoproduction off the proton are presented using transverse target polarization and data from the CEBAF Large Acceptance Spectrometer (CLAS) FROST experiment at Jefferson Lab. The beam-target asymmetry F has been measured using circularly polarized, tagged photons in the energy range 1200-2700 MeV, and the beam-target asymmetries H and P have been measured using linearly polarized, tagged photons in the energy range 1200-2000 MeV. These measurements significantly increase the database on polarization observables. The results are included in two partial-wave analyses and reveal significant contributions from several nucleon (N^{*}) resonances. In particular, contributions from new N^{*} resonances listed in the Review of Particle Properties are observed, which aid in reaching the goal of mapping out the nucleon resonance spectrum.

8.
Artigo em Inglês | MEDLINE | ID: mdl-28071589

RESUMO

Atopic dermatitis (AD) has a prevalence of 1%-3% in adults. Adult-onset AD has only been defined recently, and lack of familiarity with this condition and confusion regarding the appropriate terminology persist. AD may first appear in childhood or de novo in adults and is characterized by pronounced clinical heterogeneity. The disease often deviates from the classic pattern of flexural dermatitis, and there are forms of presentation that are specific to adults, such as head-and-neck dermatitis, chronic eczema of the hands, multiple areas of lichenification, or prurigo lesions. Although diagnosis is clinical, adult-onset AD frequently does not fit the traditional diagnostic criteria for the disease, which were developed for children. Thus, AD is often a diagnosis of exclusion, especially in de novo cases. Additional diagnostic tests, such as the patch test, prick test, skin biopsy, or blood test, are usually necessary to rule out other diseases or other types of eczema appearing concomitantly with AD. This article presents an update of the different forms of clinical presentation for AD in adults along with a proposed diagnostic approach, as new treatments will appear in the near future and many patients will not be able to benefit from them unless they are properly diagnosed.


Assuntos
Dermatite Atópica/diagnóstico , Testes Imunológicos , Pele , Adulto , Distribuição por Idade , Idade de Início , Biomarcadores/sangue , Biópsia , Dermatite Atópica/sangue , Dermatite Atópica/epidemiologia , Dermatite Atópica/imunologia , Diagnóstico Diferencial , Feminino , Humanos , Incidência , Masculino , Valor Preditivo dos Testes , Prevalência , Prognóstico , Fatores de Risco , Pele/imunologia , Pele/metabolismo , Pele/patologia
12.
Climacteric ; 19(5): 452-7, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27538242

RESUMO

OBJECTIVE: To evaluate the effect of prior bilateral oophorectomy on the intima-media thickness (IMT) of coronary and carotid arteries. METHODS: A total of 25 Wistar albino rats, aged 8-10 weeks, were assigned to three groups: ovariectomized (n = 10), control (n = 10) and sham (n = 5). The rats in the sham group only underwent midline laparotomy, while the other rats' ovaries were removed by the same type of laparotomy. All rats were sacrificed to evaluate microscopically the impact of a prolonged 26-week surgical menopause (menopausal period) on the IMT of the carotid and coronary arterial structure. RESULTS: The mean IMTs of both the carotid and coronary arteries in the ovariectomized group were significantly thicker than those of the control and sham groups (carotid arteries: 268.69 ± 53.67, 195.61 ± 47.60 and 193.86 ± 75.01 µm, p = 0.014; coronary arteries: 182.40 ± 30.22, 136.00 ± 35.82 and 165.24 ± 40.68 µm, p = 0.022, respectively). CONCLUSION: According to the results of this study, surgical menopause results in a noteworthy increase in the IMT of the carotid and coronary arteries when compared with the controls. This interventional effect may have a significant role in accelerating the process of atherosclerosis.


Assuntos
Artérias Carótidas/patologia , Espessura Intima-Media Carotídea , Vasos Coronários/patologia , Menopausa , Ovariectomia , Animais , Feminino , Distribuição Aleatória , Ratos , Ratos Wistar
13.
Clin Exp Obstet Gynecol ; 43(4): 550-554, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-29734547

RESUMO

PURPOSE: This study aimed to compare the effectiveness of EMG-biofeedback (EMG-BF), extracorporeal magnetic innervation (ExMI), and pelvic floor muscle training (PFMT) treatments on women with stress urinary incontinence (SUI). Materials and Meth- ods: The study included 67 women with SUI. Pelvic floor muscles (PFMs) were evaluated with electromyography and the quality of life (QoL) with Incontinence Quality of Life (I-QoL) questionnaire; afterwards, the subjects were divided into three groups; EMG-BF group (n=23), ExMI group (n=20), and PFMT group (n=24). EMG-BF group and ExMI group were given training in urogynecologi- cal physiotherapy clinic. PFMT group were given eight-week home exercises. Each group was assessed before training and after eight weeks. RESULTS: All three groups showed a significant improvement in EMG activity values and average QoL scores. The greatest im- provement was observed in the EMG-BF training group for QoL scores. CONCLUSIONS: This study demonstrated that all of the three methods performed with the purpose of increasing PFM strength were effective. The increase in PFM strength reduces incontinence associated symptoms and thus improves Qol.


Assuntos
Biorretroalimentação Psicológica , Eletromiografia , Terapia por Exercício , Incontinência Urinária por Estresse/terapia , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Força Muscular/fisiologia , Diafragma da Pelve/fisiologia , Qualidade de Vida , Inquéritos e Questionários , Resultado do Tratamento
14.
Actas Dermosifiliogr ; 107(8): 640-51, 2016 Oct.
Artigo em Inglês, Espanhol | MEDLINE | ID: mdl-27289134

RESUMO

The term cutaneous pseudolymphoma refers to benign reactive lymphoid proliferations in the skin that simulate cutaneous lymphomas. It is a purely descriptive term that encompasses various reactive conditions with a varied etiology, pathogenesis, clinical presentation, histology, and behavior. We present a review of the different types of cutaneous pseudolymphoma. To reach a correct diagnosis, it is necessary to contrast clinical, histologic, immunophenotypic, and molecular findings. Even with these data, in some cases only the clinical course will confirm the diagnosis, making follow-up essential.


Assuntos
Pseudolinfoma/diagnóstico , Dermatopatias/diagnóstico , Angioceratoma/diagnóstico , Angioceratoma/patologia , Diagnóstico Diferencial , Toxidermias/diagnóstico , Infecções por HIV/complicações , Humanos , Imunofenotipagem , Mordeduras e Picadas de Insetos/complicações , Doença de Lyme/complicações , Linfoma não Hodgkin/diagnóstico , Pseudolinfoma/classificação , Pseudolinfoma/etiologia , Pseudolinfoma/patologia , Dermatopatias/classificação , Dermatopatias/etiologia , Dermatopatias/patologia , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/patologia , Sífilis/induzido quimicamente , Tatuagem/efeitos adversos , Vacinação/efeitos adversos
15.
Theriogenology ; 218: 79-88, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38301510

RESUMO

The aim of the present study was to evaluate: 1) the association between AMH, AFC, superovulatory response and embryo yield in sheep; and 2) the effect of FSH treatment length during superstimulation of the first follicular wave on ovarian response and embryo yield, particularly in ewes with low and high AMH. The experiment was performed on 63 Polled Dorset ewes that received an ovarian superstimulatory treatment during the first follicular wave (Day 0 protocol). Ewes were administered a total dose of 240 mg of FSH distributed in six (6-dose regimen, n = 30) or eight (8-dose regimen, n = 33) decreasing doses administered 12 h apart. On Day -9 (random stage of the estrous cycle) and Day 0 (day of the first FSH dose) ovarian ultrasonography was performed and blood samples were collected for AFC and AMH determinations, respectively. A weak positive correlation between AMH and small AFC (follicles <4 mm) was observed (r = 0.23; P = 0.07), and AMH concentration was positively correlated (r = 0.29; P < 0.05) with the number of corpora lutea (CL) determined at embryo collection (i.e., 6 d after insemination). The length of FSH treatment tended (P = 0.06) to affect the ovarian response, such that the number of CL was greater in 8-dose than 6-dose treated ewes, while no differences (P > 0.10) in embryo yield outcomes were observed. For further analysis, ewes were classified into low (<7 ng/mL) and high (>10 ng/mL) serum AMH. In high AMH ewes, there were no differences (P > 0.05) in the number of CL nor embryo yield between the 6-dose and 8-dose treatment (e.g., 7.8 ± 2.4 and 8.3 ± 2.5 transferable embryos, respectively; P = 0.92). Conversely, for low AMH ewes, fertilized ova and embryo yield were greater (P ≤ 0.05) for ewes receiving the 8-dose than the 6-dose superstimulatory treatment (e.g., 8.4 ± 2.8 vs. 2.7 ± 0.9 transferable embryos, respectively, P ≤ 0.05). In conclusion, embryo production in poor responding ewes with low low circulating AMH is improved by extending the superstimulatory treatment length from 6 to 8 FSH doses.


Assuntos
Hormônio Foliculoestimulante , Folículo Ovariano , Feminino , Animais , Ovinos , Folículo Ovariano/fisiologia , Hormônio Foliculoestimulante/farmacologia , Ovário , Corpo Lúteo , Superovulação
16.
Gen Comp Endocrinol ; 188: 133-6, 2013 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-23410915

RESUMO

The melanocortin system integrates different agonists, competitive or inverse agonists, and receptors. Recent investigations have also discovered a specific system of melanocortin receptor accessory proteins (MRAPs) that are involved in the regulation of the functional expression of these receptors. MRAP1 mutations are responsible for type 2 familial glucocorticoid deficiency (FGD2), a rare autosomal disorder characterized by high plasma adrenocorticotropin hormone (ACTH) levels but severe cortisol deficiency. ACTH binds melanocortin 2 receptor (MC2R), a G protein-coupled receptor, in the adrenal gland to promote corticosteroid synthesis. In the absence of MRAP1, MC2R cannot translocate from the endoplasmic reticulum to the plasma membrane and ACTH-induced signaling is extinguished. A second MRAP protein, called MRAP2, also modulates MC2R activity. MRAPs also interact with the other melanocortin receptors, adjusting their pharmacological properties. In this paper, we briefly review the MRAP system and its interaction with melanocortin receptors.


Assuntos
Proteínas de Membrana/metabolismo , Receptores de Melanocortina/metabolismo , Hormônio Adrenocorticotrópico/metabolismo , Animais , Humanos , Ligação Proteica , Receptor Tipo 1 de Melanocortina/metabolismo , Receptor Tipo 2 de Melanocortina/metabolismo
19.
Eur Rev Med Pharmacol Sci ; 17(7): 895-902, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23640435

RESUMO

BACKGROUND: The gynecological laparoscopic surgery requires pneumoperitoneum (PP) with CO2 gas insufflation. CO2 PP may influence cardiac automic function (CAF). This study was conducted to assess its significance and the prolonged effects of CO2 PP on the activity of the cardiac autonomic function 24 hours after the operation by heart rate turbulence (HRT) and heart rate variability (HRV), first time in the literature. PATIENTS AND METHODS: Fifty patients scheduled for elective gynecologic laparoscopy were evaluated. The patients had no preexisting lung or heart disease or pathologic lung function. Conventional general anesthesia with midazolam, propofol, fentanyl, rocuronium, and sevoflurane was administered. ECG recordings were carried out between before 4 h from surgery and the beginning of anesthesia (T1), induction of PP and CO2 evacuation (T2) and a 24-h period postoperatively (T3). The Holter recordings of all patients were analyzed by HRT and HRV. RESULTS: There were significant reductions in in HRV and HRT parameters peri-op period compared to the pre-op values (p < 0.05). In the first 3 h of post-op period, were calculated all HRT and some HRV (SDNN, LF) parameters were also found to be significantly reduced than the values of pre-op period (p < 0.05). CONCLUSIONS: This study described adverse effects of CO2 PP on cardiac autonomic regulation in the early postoperative period according to the long-term HRV and HRT frequency analysis, for the first time in the literature. The early postoperative monitorization may supply efficacious information for arrhythmic complications.


Assuntos
Sistema Nervoso Autônomo/fisiologia , Frequência Cardíaca , Coração/inervação , Pneumoperitônio Artificial , Adulto , Feminino , Humanos , Laparoscopia , Estudos Prospectivos
20.
J Obstet Gynaecol ; 33(8): 862-4, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24219730

RESUMO

Prevalence of abnormalities in thyroid hormones and thyroid autoantibodies in patients with a history of early pregnancy loss (EPL) (n = 17) and unexplained infertility (UI) (n = 25), were compared with that of 45 control patients. TSH, antithyroid peroxidase (anti-TPO) and antithyroglobulin (anti-TG) antibody levels in UI and EPL groups were similar to that of the control group. TSH was normal in 39, 22 and 13 of control, UI and EPL patients, respectively. Among patients with a normal TSH, fT4 was higher (p < 0.001) and fT3 was lower (p < 0.001) in infertile patients when compared with the control group. Thyroid function tests seem to be associated with infertility but their association with EPL is weaker. Infertility seems to be associated with a high fT4 and low fT3 status. Thyroid autoantibodies do not seem to be associated with either infertility or EPL.


Assuntos
Perda do Embrião/etiologia , Infertilidade Feminina/etiologia , Doenças da Glândula Tireoide/complicações , Hormônios Tireóideos/sangue , Adulto , Autoanticorpos/sangue , Estudos de Casos e Controles , Perda do Embrião/sangue , Feminino , Humanos , Infertilidade Feminina/sangue , Modelos Lineares , Gravidez , Adulto Jovem
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