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1.
Clin Radiol ; 79(4): e511-e523, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38307814

RESUMEN

AIM: To explore the value of radiomics for predicting the expression of programmed death ligand 1 (PD-L1) in non-small-cell lung cancer (NSCLC) based on multiparameter spectral computed tomography (CT) images. MATERIALS AND METHODS: A total of 220 patients with NSCLC were enrolled retrospectively and divided into the training (n=176) and testing (n=44) cohorts. The radiomics features were extracted from the conventional CT images, mono-energy 40 keV images, iodine density (ID) maps, Z-effective maps, and electron density maps. The logistic regression (LR) and support vector machine (SVM) algorithms were employed to build models based on radiomics signatures. The prediction abilities were qualified by the area under the curve (AUC) obtained from the receiver operating characteristic (ROC) curve. Internal validation was performed on the independent testing dataset. RESULTS: The combined model for PD-L1 ≥1%, which consisted of the radiomics score (rad-score; p<0.0001), white blood cell (WBC; p=0.027) counts, and air bronchogram (p=0.003), reached the highest performance with the AUCs of 0.873 and 0.917 in the training and testing dataset, respectively, which was better than the radiomics model with the AUCs of 0.842 and 0.886. The combined model for PD-L1 ≥50%, which consisted of rad-score (p<0.0001) and WBC counts (p=0.027), achieved the highest performance in the training and testing dataset with AUCs of 0.932 and 0.903, respectively, which was better than the radiomics model with AUCs of 0.920 and 0.892, respectively. CONCLUSION: The radiomics model based on the multiparameter images of spectral CT can predict the expression level of PD-L1 in NSCLC. The combined model can obtain higher prediction efficiency and serves as a promising method for immunotherapy selection.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Antígeno B7-H1 , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Radiómica , Estudios Retrospectivos , Neoplasias Pulmonares/diagnóstico por imagen , Tomografía Computarizada por Rayos X
3.
Phys Rev Lett ; 129(25): 252301, 2022 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-36608250

RESUMEN

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at sqrt[s_{NN}]=193 GeV, Cu+Au at sqrt[s_{NN}]=200 GeV and Au+Au spanning the range sqrt[s_{NN}]=11.5-200 GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

4.
Phys Rev Lett ; 129(9): 092501, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-36083674

RESUMEN

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π^{0}s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π^{0} pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale Q_{s}^{2} on the mass number A. A linear scaling of the suppression with A^{1/3} is observed with a slope of -0.09±0.01.

6.
Phys Rev Lett ; 128(20): 202301, 2022 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-35657899

RESUMEN

We report precision measurements of hypernuclei _{Λ}^{3}H and _{Λ}^{4}H lifetimes obtained from Au+Au collisions at sqrt[s_{NN}]=3.0 GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of _{Λ}^{3}H and _{Λ}^{4}H midrapidity yields in Au+Au collisions at sqrt[s_{NN}]=3.0 GeV. _{Λ}^{3}H and _{Λ}^{4}H, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst) ps for _{Λ}^{3}H and 218±6(stat)±13(syst) ps for _{Λ}^{4}H. The p_{T}-integrated yields of _{Λ}^{3}H and _{Λ}^{4}H are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of _{Λ}^{4}H is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the _{Λ}^{3}H yield well, while underestimating the _{Λ}^{4}H yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured _{Λ}^{3}H and _{Λ}^{4}H yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.

7.
Phys Rev Lett ; 128(12): 122303, 2022 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-35394314

RESUMEN

Understanding gluon density distributions and how they are modified in nuclei are among the most important goals in nuclear physics. In recent years, diffractive vector meson production measured in ultraperipheral collisions (UPCs) at heavy-ion colliders has provided a new tool for probing the gluon density. In this Letter, we report the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sqrt[s_{NN}]=200 GeV in d+Au collisions. The differential cross section as a function of momentum transfer -t is measured. In addition, data with a neutron tagged in the deuteron-going zero-degree calorimeter is investigated for the first time, which is found to be consistent with the expectation of incoherent diffractive scattering at low momentum transfer. Theoretical predictions based on the color glass condensate saturation model and the leading twist approximation nuclear shadowing model are compared with the data quantitatively. A better agreement with the saturation model has been observed. With the current measurement, the results are found to be directly sensitive to the gluon density distribution of the deuteron and the deuteron breakup process, which provides insights into the nuclear gluonic structure.

8.
Phys Rev Lett ; 128(9): 092301, 2022 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-35302834

RESUMEN

The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in midcentral (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.

9.
Phys Rev Lett ; 126(16): 162301, 2021 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-33961449

RESUMEN

Global polarization of Ξ and Ω hyperons has been measured for the first time in Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements of the Ξ^{-} and Ξ[over ¯]^{+} hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay Ξ→Λ+π, as well as by measuring the polarization of the daughter Λ hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over Ξ^{-} and Ξ[over ¯]^{+}, is measured to be ⟨P_{Ξ}⟩=0.47±0.10(stat)±0.23(syst)% for the collision centrality 20%-80%. The ⟨P_{Ξ}⟩ is found to be slightly larger than the inclusive Λ polarization and in reasonable agreement with a multiphase transport model. The ⟨P_{Ξ}⟩ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of Ω, ⟨P_{Ω}⟩=1.11±0.87(stat)±1.97(syst)% was obtained by measuring the polarization of daughter Λ in the decay Ω→Λ+K, assuming the polarization transfer factor C_{ΩΛ}=1.

10.
Phys Rev Lett ; 127(9): 092301, 2021 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-34506181

RESUMEN

We report on the first measurement of charm-strange meson D_{s}^{±} production at midrapidity in Au+Au collisions at sqrt[s_{NN}]=200 GeV from the STAR experiment. The yield ratio between strange (D_{s}^{±}) and nonstrange (D^{0}) open-charm mesons is presented and compared to model calculations. A significant enhancement, relative to a pythia simulation of p+p collisions, is observed in the D_{s}^{±}/D^{0} yield ratio in Au+Au collisions over a large range of collision centralities. Model calculations incorporating abundant strange-quark production in the quark-gluon plasma and coalescence hadronization qualitatively reproduce the data. The transverse-momentum integrated yield ratio of D_{s}^{±}/D^{0} at midrapidity is consistent with a prediction from a statistical hadronization model with the parameters constrained by the yields of light and strange hadrons measured at the same collision energy. These results suggest that the coalescence of charm quarks with strange quarks in the quark-gluon plasma plays an important role in D_{s}^{±}-meson production in heavy-ion collisions.

11.
Phys Rev Lett ; 127(5): 052302, 2021 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-34397228

RESUMEN

The Breit-Wheeler process which produces matter and antimatter from photon collisions is experimentally investigated through the observation of 6085 exclusive electron-positron pairs in ultraperipheral Au+Au collisions at sqrt[s_{NN}]=200 GeV. The measurements reveal a large fourth-order angular modulation of cos4Δϕ=(16.8±2.5)% and smooth invariant mass distribution absent of vector mesons (ϕ, ω, and ρ) at the experimental limit of ≤0.2% of the observed yields. The differential cross section as a function of e^{+}e^{-} pair transverse momentum P_{⊥} peaks at low value with sqrt[⟨P_{⊥}^{2}⟩]=38.1±0.9 MeV and displays a significant centrality dependence. These features are consistent with QED calculations for the collision of linearly polarized photons quantized from the extremely strong electromagnetic fields generated by the highly charged Au nuclei at ultrarelativistic speed. The experimental results have implications for vacuum birefringence and for mapping the magnetic field which is important for emergent QCD phenomena.

12.
Phys Rev Lett ; 127(26): 262301, 2021 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-35029466

RESUMEN

According to first-principle lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region µ_{B}≤T_{c}. In this range the ratio, C_{6}/C_{2}, of net-baryon distributions are predicted to be negative. In this Letter, we report the first measurement of the midrapidity net-proton C_{6}/C_{2} from 27, 54.4, and 200 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). The dependence on collision centrality and kinematic acceptance in (p_{T}, y) are analyzed. While for 27 and 54.4 GeV collisions the C_{6}/C_{2} values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the C_{6}/C_{2} ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high-energy nuclear collisions at top RHIC energy.

13.
Phys Rev Lett ; 126(9): 092301, 2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33750161

RESUMEN

Nonmonotonic variation with collision energy (sqrt[s_{NN}]) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the quantum chromodynamics critical point. We report the first evidence of a nonmonotonic variation in the kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of sqrt[s_{NN}] with 3.1 σ significance for head-on (central) gold-on-gold (Au+Au) collisions measured solenoidal tracker at Relativistic Heavy Ion Collider. Data in noncentral Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of sqrt[s_{NN}].

14.
J Neural Transm (Vienna) ; 128(11): 1663-1675, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34333693

RESUMEN

Cervical dystonia (CD) is a neurological movement disorder causing the neck to move involuntarily away from the neutral position. CD is a network disorder, involving multiple brain areas and, therefore, may impair movement in parts of the body other than the neck. This study used clinical assessments to investigate walking, balance and upper limb function (UL) in people with CD; the reliability of scoring these assessments and examined for relationship between CD severity, usual exercise and clinical assessments. We conducted a prospective observational cohort study of participants with isolated, focal, idiopathic CD. Participants were assessed by experienced physiotherapists and completed three questionnaires and eight clinical assessments of fear of falling, balance confidence, walking, balance, UL function and usual exercise. Results were compared to published data from healthy adults and other neurological populations. Twenty-two people with mild to moderate CD participated. Fear of falling, gross UL function and usual exercise were worse in people with CD compared with healthy adults, while walking, balance and distal UL function were similar to healthy populations. All assessments were reliably performed by physiotherapists, and we found no correlations between the severity of dystonia or usual exercise and performance on the physical assessments. Routine performance of clinical assessment of walking and balance are likely not required in people with mild to moderate CD; however, fear of falling and gross upper limb function should be assessed to determine any problems which may be amenable to therapy.


Asunto(s)
Tortícolis , Caminata , Accidentes por Caídas , Adulto , Estudios Transversales , Miedo , Humanos , Equilibrio Postural , Estudios Prospectivos , Reproducibilidad de los Resultados , Extremidad Superior
15.
Clin Radiol ; 76(4): 316.e19-316.e28, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33551151

RESUMEN

AIM: To evaluate the postoperative magnetic resonance imaging (MRI) findings of intracranial foreign body granulomas (FBGs) and true recurrent tumours (RTs) and thus lead to a basis for management decision-making. MATERIALS AND METHODS: Twenty-two patients with previous brain tumour surgery were diagnosed clinically with RT and underwent surgery. Re-operative pathology revealed FBG in eight patients and RT in 14 patients. MRI findings before the initial operation were compared to those before the re-operation. RESULTS: Features of FBGs versus RTs on MRI were as follows: (1) mean lesion size: 1.3 ± 0.7 (0.5-2.6) versus 3.2 ± 1.7 (1.1-6.3) cm (p=0.001, odds ratio [OR] = 4.18); (2) hypointensity on T2-weighted imaging (WI): 6/8 (75%) versus 0/14 (0%; p<0.001, OR=75.4); (3) non-restricted diffusion on diffusion-WI (DWI): 6/8 (75%) versus 2/14 (14.3%; p=0.008, OR=18); and (4) "ring and bubble" appearance on contrast-enhanced T1WI: 7/8 (87.5%) versus 2/14 (14.3%; p=0.001, OR=42). In comparison with their original tumours, the FBGs in the FBG group showed significantly lower T2 signal intensity, lower signal on DWI, and more cases of non-restricted diffusion on DWI (p=0.04, 0.04, 0.04, respectively). CONCLUSION: On brain MRI, FBGs can be differentiated from RTs by their relatively smaller size, hypointensity on T2WI, lack of restricted diffusion on DWI, and "ring and bubble" appearance on contrast-enhanced T1WI. Comparing the MRI findings of the focal lesion in the tumour bed with those of the original tumour is suggested to enhance diagnostic confidence.


Asunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Granuloma de Cuerpo Extraño/diagnóstico por imagen , Imagen por Resonancia Magnética , Recurrencia Local de Neoplasia/diagnóstico por imagen , Complicaciones Posoperatorias/diagnóstico por imagen , Adolescente , Adulto , Anciano , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/cirugía , Niño , Preescolar , Toma de Decisiones Clínicas , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Granuloma de Cuerpo Extraño/patología , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Recurrencia Local de Neoplasia/cirugía , Complicaciones Posoperatorias/patología , Reoperación , Adulto Joven
16.
Phys Rev Lett ; 124(17): 172301, 2020 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-32412276

RESUMEN

We report on the first measurement of the charmed baryon Λ_{c}^{±} production at midrapidity (|y|<1) in Au+Au collisions at sqrt[s_{NN}]=200 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider. The Λ_{c}/D^{0} [denoting (Λ_{c}^{+}+Λ_{c}^{-})/(D^{0}+D[over ¯]^{0})] yield ratio is measured to be 1.08±0.16 (stat)±0.26 (sys) in the 0%-20% most central Au+Au collisions for the transverse momentum (p_{T}) range 3

17.
Zhonghua Yi Xue Za Zhi ; 100(21): 1668-1675, 2020 Jun 02.
Artículo en Zh | MEDLINE | ID: mdl-32486604

RESUMEN

Objective: To study the effects of miR-16-5p on proliferation, migration and invasion of osteosarcoma cells and its mechanism. Methods: Quantitative polymerase chain reaction (qPCR) and Western blotting were used to detect the mRNA and protein expression of miR-16-5p and TSPAN15 in human normal osteoblasts hFOB 1.19 and osteosarcoma cells MG63, Saos2 and HOS. The miR-16-5p or si-TSPAN15 was transfected into MG63 cells to observe its role in cell proliferation, migration and invasion. Cell proliferation was measured with MTT assay, cell migration and invasion were examined by Transwell, and the protein expression of CyclinD1, matrix metalloproteinase 2 (MMP-2), MMP-9, tetraspanin 15 (TSPAN15), phospha-tidylinositol3-kinase(p-PI3K) and phospha-protein kinase B(p-AKT) were determined by using Western blotting. The starbase website prediction combined with dual luciferase gene reporter assay was performed to analyze the targeting relationship between miR-16-5p and TSPAN15. miR-16-5p and pcDNA-TSPAN1 were co-transfected to assess the effect of high expression of TSPAN15 on overexpression of miR-16-5p-induced proliferation, migration and invasion of MG63 cells. Data comparison between the two groups was performed by using t test. Results: Compared with hFOB 1.19 cells (1.00±0.12), the expression of miR-16-5p was significantly decreased in MG63, Saos2 and HOS cells (0.32±0.05, 0.40±0.04, 0.45±0.06, respectively)(F=156.204, P<0.05), and TSPAN15 mRNA and protein levels were greatly increased (F=71.718, 110.350, both P<0.05). Overexpression of miR-16-5p obviously reduced the expression of CyclinD1, MMP-2, MMP-9 protein, cell viability, cell migration and invasion (F=150.136,117.228, 154.971, 89.479, 98.373, 130.880, all P<0.05) in MG63 cells. Knockdown of TSPAN15 greatly reduced CyclinD1, MMP-2, MMP-9 protein levels, cell survival rate, cell migration, and invasion number (F=93.206, 107.030, 109.326, 115.625, 146.113, 139.300, all P<0.05). Overexpression of miR-16-5p markedly decreased the expression of p-PI3K and p-AKT protein in MG63 cells (F=156.755, 181.419, both P<0.05). miR-16-5p targeted to regulate the expression of TSPAN15. High expression of TSPAN15 partially reversed the inhibitory effect of miR-16-5p on TSPAN15, CyclinD1, MMP-2, MMP-9, p-PI3K, p-AKT protein expression, cell viability, cell migration number and invasion number in MG63 cells. Conclusion: miR-16-5p inhibits the proliferation, migration and invasion of osteosarcoma cells by targeting the TSPAN15 gene and regulating the PI3K/AKT signaling pathway.


Asunto(s)
Neoplasias Óseas , MicroARNs/genética , Osteosarcoma , Neoplasias Óseas/genética , Línea Celular Tumoral , Movimiento Celular , Proliferación Celular , Humanos , Invasividad Neoplásica , Osteosarcoma/genética , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Transducción de Señal , Tetraspaninas
18.
Zhonghua Yi Xue Za Zhi ; 100(2): 141-145, 2020 Jan 14.
Artículo en Zh | MEDLINE | ID: mdl-31937055

RESUMEN

Objective: To observe the effect of autophagy of tibial growth plate chondrocyte on apoptosis in chronic renal insufficiency (CRI) rats. Methods: Male 4-week-old SD rats were randomly divided into two groups: (1) Sham group: only the left ureter was exposed (n=10); (2) CRI group: the left ureter was ligated to cause CRI (n=10). The urine from all the rats was collected 6 weeks after the operation and the total protein content was measured. Then all the rats were sacrificed and the concentrations of creatinine and urea nitrogen in intracardiac blood were detected. The proximal tibia were fixed and decalcified to prepare histological sections, and the number of chondrocytes of column cells in the proliferative area of tibia growth plate was observed by saffron O staining. The expression rate of protein Light Chain-3, an autophagy marker of chondrocytes, was detected by immunofluorescence. The apoptosis rate of chondrocytes was detected by the method of TUNEL assay. The level of glycogenin-1, a glycogen formation marker of chondrocyte was detected by immunohistochemistry in chondrocytes. Results: The 24 h urine total protein was higher in CRI group [(163.5±11.3) mg vs (38.6±9.8) mg, t=25.620, P<0.001]. The levels of blood creatinine [(67.3±16.2) µmol/L vs (28.4±11.5) µmol/L, t=5.974, P<0.001] and urea nitrogen [(16.4±6.4) mmol/L vs (4.8±2.0) mmol/L, t=5.198, P<0.001] were higher in CRI group. The number of chondrocytes of column cells in the proliferating area of tibia growth plate was lower in CRI group (4.2±2.1 vs 9.1±3.8, t=3.109, P=0.006). The expression rate of LC-3 protein in chondrocytes of CRI group was lower [(27.2±12.6)% vs (51.4±18.2)%, t=3.457, P=0.003]. The level of glycogenin-1 of chondrocytes in CRI group increased significantly (6.1±2.5 vs 3.5±1.8, t=2.669, P=0.016). The apoptosis rate of chondrocytes in CRI group also increased [(17.2±4.8)% vs (5.1±3.4)%, t=6.505, P<0.001]. Conclusion: Malfunction of autophagy in tibial growth plate chondrocytes causes increased apoptosis rate in CRI rats, which might be caused by the failure of glycogen degradation in chondrocytes.


Asunto(s)
Autofagia , Insuficiencia Renal Crónica , Animales , Apoptosis , Condrocitos , Placa de Crecimiento , Masculino , Ratas , Ratas Sprague-Dawley , Tibia
19.
Fa Yi Xue Za Zhi ; 36(1): 52-60, 2020 Feb.
Artículo en Inglés, Zh | MEDLINE | ID: mdl-32250079

RESUMEN

ABSTRACT: Objective To discuss the activation characteristics of the prefrontal cortex of people with mild cognitive impairment (MCI) due to brain trauma during working memory tasks. Methods The psychological experiment design software E-prime was used and N-back paradigm was adopted as working memory task. Functional near-infrared spectroscopy (fNIRS) was used to detect changes in cortical oxygenated hemoglobin concentrations of 22 channels within the prefrontal lobe of 24 people with MCI due to brain trauma (study group) and 27 healthy volunteers (control group) with matching gender and age. Behavioral data, such as the number of keystroke errors and reaction time, were recorded simultaneously. Independent samples t test and non-parametric test were used to compare the mean value of oxygenated hemoglobin concentration change, the number of key errors and the mean value of reaction time of the two groups in each task. Results (1) The differences in the number of errors and reaction time between the two groups in 1-back and 2-back tasks had statistical significance (P<0.05).The main effects of task load and group were both significant (task F=14.11, P=0.001 1; group F=10.39, P=0.001 5). (2) During the 1-back task, the differences in oxygenated hemoglobin concentration changes of the 22 channels between the two groups had no statistical significance (P>0.05). During the 2-back task, the differences in oxygenated hemoglobin concentration changes of the two groups in channel 2, 3, 7, 9, 10, 11, 14, 15, 18, 19, 21 and 22 had statistical significance (P<0.05). (3) In the 1-back task, the left frontal pole and dorsolateral prefrontal area in both groups were activated. In the 2-back task, the activation areas of the control group were the left frontal pole area and the left dorsolateral prefrontal area, while that of the study group almost covered most of the left and right frontal pole areas, which were scattered and the right area was activated, too. Conclusion Patients with MCI due to brain trauma have obvious working memory impairment, and during the 2-back working memory task, the activation of the prefrontal lobe decreased, but the activation range was wider.


Asunto(s)
Lesiones Traumáticas del Encéfalo , Disfunción Cognitiva , Lesiones Traumáticas del Encéfalo/complicaciones , Disfunción Cognitiva/etiología , Humanos , Memoria a Corto Plazo , Corteza Prefrontal , Espectroscopía Infrarroja Corta
20.
Phys Rev Lett ; 122(17): 172301, 2019 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-31107064

RESUMEN

The first (v_{1}^{fluc}), second (v_{2}), and third (v_{3}) harmonic coefficients of the azimuthal particle distribution at midrapidity are extracted for charged hadrons and studied as a function of transverse momentum (p_{T}) and mean charged particle multiplicity density ⟨N_{ch}⟩ in U+U (sqrt[s_{NN}]=193 GeV), Au+Au, Cu+Au, Cu+Cu, d+Au, and p+Au collisions at sqrt[s_{NN}]=200 GeV with the STAR detector. For the same ⟨N_{ch}⟩, the v_{1}^{fluc} and v_{3} coefficients are observed to be independent of the collision system, while v_{2} exhibits such a scaling only when normalized by the initial-state eccentricity (ϵ_{2}). The data also show that ln(v_{2}/ϵ_{2}) scales linearly with ⟨N_{ch}⟩^{-1/3}. These measurements provide insight into initial-geometry fluctuations and the role of viscous hydrodynamic attenuation on v_{n} from small to large collision systems.

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