酰胺质子转移加权成像与体素内不相干运动成像评估肺腺癌病理分级及其与SUVmax的相关性

目的旨在比较酰胺质子转移加权成像(amide proton transfer weighted imaging,APTWI)和体素内不相干运动成像(intravoxel incoherent motion,IVIM)在评估肺腺癌病理分级中的价值,并评估各参数与18F-FDG正电子发射计算机断层显像(positron emission tomography,PET)的最大标准化摄取值(maximum standard uptake value,SUVmax)的相关性。材料与方法前瞻性收集66例术后病理证实为肺腺癌的患者,对APTWI、IVIM和18F-FDG PET图像进行分析,分别测量非对称磁化转移率[magnetization transfer ratio asymmetry,MTRasym(3.5 ppm)]、扩散系数(D)、假扩散系数(D*)、灌注分数(f)值、扩散分布指数(DDC)、扩散异质性指数(α)及最大标准化摄取值(SUVmax)。对比分析不同分级组间各参数的差异及诊断效能,并评估各参数值与SUVmax间的相关性。结果低分化组的MTRasym(3.5 ppm)、f值高于中高分化组,而D、DDC值低于中高分化组(P均<0.05),两组间D*、α值差异无统计学意义。MTRasym(3.5 ppm)、D、DDC、f、α和D*值诊断肺腺癌病理分级的AUC依次是0.858、0.743、0.661、0.645、0.577、0.531,MTRasym(3.5 ppm)的诊断效能显著高于除D值以外的其他参数(P均<0.05)。APTWI与IVIM联合鉴别病理分级的诊断效能最高(AUC=0.973)。MTRasym(3.5 ppm)与SUVmax值呈弱正相关(r=0.396);D、DDC值分别与SUVmax值呈弱负相关(r=-0.359,-0.249,P均<0.05)。结论APTWI和IVIM均是鉴别肺腺癌病理分级的有效手段,APTWI参数的诊断效能较IVIM更加有优势,部分参数与SUVmax存在相关性。

Method for Fault Feature Selection for a Baler Gearbox Based on an Improved Adaptive Genetic Algorithm

The performance and efficiency of a baler deteriorate as a result of gearbox failure.One way to overcome this challenge is to select appropriate fault feature parameters for fault diagnosis and monitoring gearboxes.This paper proposes a fault feature selection method using an improved adaptive genetic algorithm for a baler gearbox.This method directly obtains the minimum fault feature parameter set that is most sensitive to fault features through attribute reduction.The main benefit of the improved adaptive genetic algorithm is its excellent performance in terms of the efficiency of attribute reduction without requiring prior information.Therefore,this method should be capable of timely diagnosis and monitoring.Experimental validation was performed and promising findings highlighting the relationship between diagnosis results and faults were obtained.The results indicate that when using the improved genetic algorithm to reduce 12 fault characteristic parameters to three without a priori information,100%fault diagnosis accuracy can be achieved based on these fault characteristics and the time required for fault feature parameter selection using the improved genetic algorithm is reduced by half compared to traditional methods.The proposed method provides important insights into the instant fault diagnosis and fault monitoring of mechanical devices.

Resonance and antiresonance characteristics in linearly delayed Maryland model

The Maryland model is a critical theoretical model in quantum chaos.This model describes the motion of a spin-1/2particle on a one-dimensional lattice under the periodical disturbance of the external delta-function-like magnetic field.In this work,we propose the linearly delayed quantum relativistic Maryland model(LDQRMM)as a novel generalization of the original Maryland model and systematically study its physical properties.We derive the resonance and antiresonance conditions for the angular momentum spread.The“characteristic sum”is introduced in this paper as a new measure to quantify the sensitivity between the angular momentum spread and the model parameters.In addition,different topological patterns emerge in the LDQRMM.It predicts some additions to the Anderson localization in the corresponding tight-binding systems.Our theoretical results could be verified experimentally by studying cold atoms in optical lattices disturbed by a linearly delayed magnetic field.

Finding Short-Range Parity-Time Phase-Transition Points with a Neural Network

The non-Hermitian PT-symmetric system can live in either unbroken or broken PT-symmetric phase. The separation point of the unbroken and broken PT-symmetric phases is called the PT-phase-transition point.Conventionally, given an arbitrary non-Hermitian PT-symmetric Hamiltonian, one has to solve the corresponding Schrodinger equation explicitly in order to determine which phase it is actually in. Here, we propose to use artificial neural network(ANN) to determine the PT-phase-transition points for non-Hermitian PT-symmetric systems with short-range potentials. The numerical results given by ANN agree well with the literature, which shows the reliability of our new method.

Time series canopy phenotyping enables the identification of genetic variants controlling dynamic phenotypes in soybean

Advances in plant phenotyping technologies are dramatically reducing the marginal costs of collecting multiple phenotypic measurements across several time points.Yet,most current approaches and best statistical practices implemented to link genetic and phenotypic variation in plants have been developed in an era of single-time-point data.Here,we used time-series phenotypic data collected with an unmanned aircraft system for a large panel of soybean(Glycine max(L.)Merr.)varieties to identify previously uncharacterized loci.Specifically,we focused on the dissection of canopy coverage(CC)variation from this rich data set.We also inferred the speed of canopy closure,an additional dimension of CC,from the time-series data,as it may represent an important trait for weed control.Genome-wide association studies(GWASs)identified 35 loci exhibiting dynamic associations with CC across developmental stages.The time-series data enabled the identification of 10 known flowering time and plant height quantitative trait loci(QTLs)detected in previous studies of adult plants and the identification of novel QTLs influencing CC.These novel QTLs were disproportionately likely to act earlier in development,which may explain why they were missed in previous single-time-point studies.Moreover,this time-series data set contributed to the high accuracy of the GWASs,which we evaluated by permutation tests,as evidenced by the repeated identification of loci across multiple time points.Two novel loci showed evidence of adaptive selection during domestication,with different genotypes/haplotypes favored in different geographic regions.In summary,the time-series data,with soybean CC as an example,improved the accuracy and statistical power to dissect the genetic basis of traits and offered a promising opportunity for crop breeding with quantitative growth curves.

Research on two-proton radioactivity in density-dependent cluster model

The density-dependent cluster model(DDCM) provides a unified framework to study α decay,heavy-cluster radioactivity,and proton emission.Two-proton(2p) radioactivity is a rare decay mode of exotic nuclei near or beyond the drip-line.It is of great interest to explore the applicability of DDCM to this exotic decay mode.In this work,DDCM has been extended to study 2p radioactivity.The 2p-radioactivity half-lives are calculated for several known 2p-emitters,including19Mg,45Fe,48Ni,54Zn,and67Kr.The theoretical results are in good agreement with the experimental data,with the standard deviations comparable to or smaller than those given by some other theoretical models and empirical formulas.We also predict the half-lives of a number of possible 2p-emitters with S2p<0 and Sp> 0 using the new data from AME2020 and NUBASE2020.These predictions serve as useful references for future experimental and theoretical investigations on 2p radioactivity.

假体周围感染遗传易感性的研究现状

关节置换术后假体周围感染是人工关节置换术后的严重并发症之一,给患者经济、心理、生活带来严重的负担。其发病机制尚未明确。近年来随着基因测序技术的发展,对复杂疾病进行遗传分析已成为当下热点。本文综述了白细胞介素、甘露糖结合凝集素、Toll样受体、肿瘤坏死因子等单核苷酸多态性在关节置换术后假体周围感染中的遗传易感性。

利用改进的方势阱集团模型研究偶偶核的α衰变

方势阱集团模型是研究原子核α衰变的一个理论模型,具有形式简洁、计算方便等优点,可以较好地解释一些偶偶核的α衰变实验数据.方势阱集团模型假设不同的偶偶核具有相同的势阱深度,这只是真实α-子核相互作用的粗糙近似.我们改进了方势阱集团模型,在保留其优点的同时,进一步合理计入势阱深度对原子核质量数和质子数的依赖.利用改进的方势阱集团模型,研究了中等质量区、重核区和超重核区115个偶偶核的α衰变性质.结果显示,改进的方势阱集团模型给出的偶偶核α衰变半衰期理论值与实验值均方根偏差值为0.2223,相比方势阱集团模型下降了36%,尤其对于中等质量区N=Z=50附近的核素,由改进的方势阱集团模型计算的结果与实验值符合很好,说明改进的方势阱集团模型可以更好地解释α衰变半衰期实验数据.此外,我们还利用改进的方势阱集团模型预言了重核区与超重核区一些未知核素的α衰变半衰期,相关理论结果对偶偶核α衰变的实验和理论研究具有一定的参考价值.

Plasma metabolic biomarkers for syndrome of phlegm and blood stasis in hyperlipidemia and atherosclerosis

OBJECTIVE:To explore the plasma metabolite profiles in patients with the syndrome of phlegm and blood stasis in hyperlipidemia and atherosclerosis(As),and to search for the metabolic biomarkers of the syndrome.METHODS:The plasma metabolite profiles of 31 patients with the syndrome of phlegm and blood stasis in hyperlipidemia and As,6 patients with syndromes without phlegm and blood stasis,and 10 healthy subjects were analyzed by gas chromatography-mass spectrometry(GC-MS).Partial least squares-discriminant analyses(PLS-DA) were used to carry out the pattern-recognition analyses of the data.The plasma metabolic biomarkers of patients were obtained by variable importance plot value(VIP value) and Student's t-test.The structures of biomarkers were defined by the National Institute of Standards andTechnology(NIST) database.RESULTS:PLS-DA score plots of plasma metabolomes did not show overlap between the phlegm-blood stasis syndrome group and syndromes without phlegm and blood stasis group,whereas significant differences in the concentrations in the plasma of 5 metabolites were found(P< 0.05).They were identified as urine,isoleucine,glucuronic acid,palmitic acid and glycerol by searching in NIST database.The concentrations of four metabolites in the plasma of patients with syndrome of phlegm and blood stasis were higher than those with syndromes without phlegm and blood stasis,whereas the glycerol concentration was lower.CONCLUSION:Compared with patients with syndromes without phlegm and blood stasis,five metabolites showed abnormal levels in patients with the syndrome of phlegm and blood stasis.These metabolites could be diagnostic and prognostic biomarkers.

Theoretical predictions on α-decay properties of some unknown neutrondeficient actinide nuclei using machine learning

Neutron-deficient actinide nuclei provide a valuable window to probe heavy nuclear systems with large proton-neutron ratios. In recent years, several new neutron-deficient Uranium and Neptunium isotopes have been observed using α-decay spectroscopy [Z. Y. Zhang et al., Phys. Rev. Lett. 122, 192503(2019);L. Ma et al., Phys. Rev.Lett. 125, 032502(2020);Z. Y. Zhang et al., Phys. Rev. Lett. 126, 152502(2021)]. In spite of these achievements,some neutron-deficient key nuclei in this mass region are still unknown in experiments. Machine learning algorithms have been applied successfully in different branches of modern physics. It is interesting to explore their applicability in α-decay studies. In this work, we propose a new model to predict the α-decay energies and half-lives within the framework based on a machine learning algorithm called the Gaussian process. We first calculate the α-decay properties of the new actinide nucleus 214 U. The theoretical results show good agreement with the latest experimental data, which demonstrates the reliability of our model. We further use the model to predict the α-decay properties of some unknown neutron-deficient actinide isotopes and compare the results with traditional models. The results may be useful for future synthesis and identification of these unknown isotopes.

α Decays in Superstrong Static Electric Fields

Superstrong static electric fields could deform Coulomb barriers between α clusters and daughter nuclei,and bring up the possibility of speeding up α decays. We adopt a simplified model for the spherical α emitter^(212)Po and study its responses to superstrong static electric fields. We find that superstrong electric fields with field strengths|E|～0.1 MV/fm could turn the angular distribution of α emissions from isotropic to strongly anisotropic, and speed upα decays by more than one order of magnitude. We also study the influences of superstrong electric fields along the Po isotope chains, and discuss the implications of our studies on α decays in superstrong monochromatic laser fields. The study here might be helpful for future theoretical studies of α decay in realistic superstrong laser fields.

Two New Hyperon Coupling Models in the Light of the Massive Neutron Star PSR J0348+0432

In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron PSR J0348+0432.The radius of PSR J0348+0432 given by the limitation model is found to be 12.52 km^12.97 km,while the radius given by the potential well depth model is found to be 12.19 km^12.89 km.We also calculate the gravitational redshift of PSR J0348+0432 within these two models,for which the limitation model gives 0.346~0.391 and the potential well depth model gives 0.350~0.409.Further exploration of these two models shows that,these two models are almost degenerate for neutron stars lighter than 1.85 M⊙,and start to give different results for massive neutron stars heavier than 1.85 M⊙.Therefore,the studies of massive neutron stars could be crucial for discriminating these two models and help deepen our understanding of hyper-nuclear interactions.

Two-neutron halo state of ^(15)B around 3.48 MeV by a three-body model

We investigate low-lying bound states of the neutron-rich nucleus ^15B by assuming it is a three-body system made of an inert core 13 B and two valence neutrons. The three-body wave functions are obtained using the Faddeev formalism. Special attention is paid to the excited state at 3.48（6） MeV observed in the 13 C（14 C,12 N）15 B reaction, whose properties are less clear theoretically. In our three-body model, besides the ground state 3/21, a second 3/22^-state is discovered at around 3.61 MeV, which might be identified with the excited state observed at3.48（6） MeV. We study this 3/22^-state in detail. It turns out to be a two-neutron halo state with a large matter radius rm≈4.770 fm. ＆nbsp

Woods-Saxon-Gaussian potential and alpha-cluster structures of alpha + closed shell nuclei

The Woods-Saxon-Gaussian （WSG） potential is proposed as a new phenomenological potential to sys- tematically describe the level scheme, electromagnetic transitions, and alpha-decay half-lives of tile alpha-cluster structures in various alpha ＋ closed shell nuclei. It modifies the original Woods Saxon （WS） potential with a shifted Gaussian factor centered at the nuclear surface. The free parameters in the WSG potential are determined by reproducing the correct level scheme of ^212Po=^208Pb＋α. It is found that the resulting WSG potential matches the NI3Y double-folding potential at tile surface region and makes corrections to the inner part of the cluster-core l）otential. It was also determined that the WSG potential, with nearly identical parameters to that of ^212Po （except for a rescale（l radius）, could also be used to describe alpha-cluster structures in ^20Ne=^16O＋α and ^44Ti = ^40Ca＋α. In all lhrec cases, the calculated values of the level schemes, electromagnetic transitions, and alpha-decay half-lives agree with the experimental data. which indicates that the WSG potential could indeed capture many important features of the alpha-cluster structures in alpha ＋ closed shell nuclei. This study is a useful complement to the existing cluster-core potentials ill literature. The Gaussian form factor centered at the nuclear surface might also help to improve our understailding of the alpha-cluster formation, which occurs in the same general region.