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Abstract Background Long-term exposure to a high altitude environment with low pressure and low oxygen could cause abnormalities in the structure and function of the heart. Myocardial strain is a sensitive indicator for assessing myocardial dysfunction, monitoring myocardial strain is of great significance for the early diagnosis and treatment of high altitude heart-related diseases. This study applies cardiac magnetic resonance tissue tracking technology (CMR-TT) to evaluate the changes in left ventricular myocardial function and structure in rats in high altitude environment. Methods 6-week-old male rats were randomized into plateau hypoxia rats (plateau group, n = 21) as the experimental group and plain rats (plain group, n = 10) as the control group. plateau group rats were transported from Chengdu (altitude: 360 m), a city in a plateau located in southwestern China, to the Qinghai-Tibet Plateau (altitude: 3850 m), Yushu, China, and then fed for 12 weeks there, while plain group rats were fed in Chengdu(altitude: 360 m), China. Using 7.0 T cardiac magnetic resonance (CMR) to evaluate the left ventricular ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), as well as myocardial strain parameters including the peak global longitudinal (GLS), radial (GRS), and circumferential strain (GCS). The rats were euthanized and a myocardial biopsy was obtained after the magnetic resonance imaging scan. Results The plateau rats showed more lower left ventricular GLS and GRS (P 0.05). Conclusions After 12 weeks of exposure to high altitude low-pressure hypoxia environment, the left ventricular global strain was partially decreased and myocardium is damaged, while the whole heart ejection fraction was still preserved, the myocardial strain was more sensitive than the ejection fraction in monitoring cardiac function.

Recent literature has stated that the physical characteristics of natural satellites in Jupiter’s Ananke and Carme groups, such as mass, exhibit the same statistical law, with the best-fitting distribution being a Loglogistic distribution. This paper establishes dynamical equations for the variable-mass restricted three-body problem based on this new statistical law. In addition to discussing the influence of the Jacobian constant related to the system energy on the accessible region of the third body, it also uses the Lindstedt–Poincaré perturbation method to give an analytical periodic orbit of second- and third-order around the triangular Lagrangian point. Numerical simulations show that as the value of the variable mass parameter of the third body becomes smaller, the corresponding periodic orbit is affected less and less.

Considering the interaction among matter, vacuum, and radiation, this paper investigates the evolution of cosmic dynamics of the varying-vacuum model in a case of Finslerian geometry through dynamic analysis methods. Surprisingly, this model can alleviate the coincidence problem and allows for a stable later cosmological solution corresponding to the accelerating universe.

This paper investigates the dynamics of the timelike and null geodesics near the Bardeen-AdS black hole immersed in quintessence. Specifically, the equation of geodesic motion is derived by solving the Hamilton–Jacobi equation of the test particles, including the timelike particles, neutrinos, and photons. Due to the nonlinear electrodynamics’ effect on this black hole spacetime, photon motion is governed by the effective geometry, not the spacetime geometry. Furthermore, the study examines attracting, escaping, and bound orbits, and illustrates some orbits with intriguing shapes. The test particles’ circular orbits (general circular orbits and innermost/outermost stable circular orbits) are discussed in detail, wherein these orbits are principally affected by the impact parameter, the magnetic charge, and the quintessential normalization constant. In particular, the presence of quintessence makes the spacetime structure of the black hole more complex. This results in a greater number of circular orbits for the particles around it and a more diverse shape for the curve of the radius of the circular orbit with the magnetic charge. The stability of the timelike geodesics is analyzed by calculating the Lyapunov exponent. In addition, the properties of black hole horizons are presented. Finally, the critical magnetic charge and critical quintessential normalization constant, with which two horizons merge into one, are discussed.

Abstract Background In previous studies, haemorrhage occurred only with large infarct sizes, and studies found a moderate correlation between the extent of necrosis and haemorrhage, but the extent of infarction size in these studies was limited. This study aimed to find the correlations between intramyocardial haemorrhage (IMH), myocardial infarction (MI), and myocardial oedema (ME) from small to large sizes of MI in a 7.0-T MR scanner. Methods Different sizes of myocardial infarction were induced by occluding different sections of the proximal left anterior descending coronary artery (1–3 mm under the left auricle). T2*-mapping, T2-mapping and late gadolinium enhancement (LGE) sequences were performed on a 7.0 T MR system at Days 2 and 7. T2*- and T2-maps were calculated using custom-made software. All areas were expressed as a percentage of the entire myocardial tissue of the left ventricle. The rats were divided into two groups based on the T2* results and pathological findings; MI with IMH was referred to as the + IMH group, while MI without IMH was referred to as the –IMH group. Results The final experimental sample consisted of 25 rats in the + IMH group and 10 rats in the –IMH group. For the + IMH group on Day 2, there was a significant positive correlation between IMH size and MI size (r = 0.677, P

Abstract Background Despite that machine learning (ML)-based MRI has been evaluated for diagnosis of axillary lymph node metastasis (ALNM) in breast cancer patients, diagnostic values they showed have been variable. In this study, we aimed to assess the use of ML to classify ALNM on MRI and to identify potential covariates that might influence the diagnostic performance of ML. Methods A systematic research of PubMed, Embase, Web of Science, and the Cochrane Library was conducted until 27 December 2020 to collect the included articles. Subgroup analysis was also performed. Findings Fourteen studies assessing a total of 2247 breast cancer patients were included in the analysis. The overall AUC for ML in the validation set was 0.80 (95% confidence interval [CI] 0.76–0.83) with a negative predictive value of 0.83. The pooled sensitivity and specificity were 0.79 (95% CI 0.74–0.84) and 0.77 (95% CI 0.73–0.81), respectively. In the subgroup analysis of the validation set, T1-weighted contrast-enhanced (T1CE) imaging with ML yielded a higher sensitivity (0.80 vs. 0.67 vs. 0.76) than the T2-weighted fat-suppressed (T2-FS) imaging and diffusion-weighted imaging (DWI). Support vector machines (SVMs) had a higher specificity than linear regression (LR) and linear discriminant analysis (LDA) (0.79 vs. 0.78 vs. 0.75), whereas LDA showed a higher sensitivity than LR and SVM (0.83 vs. 0.70 vs. 0.77). Interpretation MRI sequences and algorithms were the main factors that affect the diagnostic performance of ML. Although its results were encouraging with the pooled sensitivity of around 0.80, it meant that 1 in 5 women that would go with undetected metastases, which may have a detrimental effect on the overall survival for 20% of patients with positive SLN status. Despite that a high NPV of 0.83 meant that ML could potentially benefit those with negative SLN, it might also translate to 1 in 5 tests being false negative. We would like to suggest that ML may not be yet usable in clinical routine especially when patient survival is used as a primary measurement of its outcome.

Abstract Background This study investigates the segmental myocardial strain of the early phase of intramyocardial hemorrhage (IMH) caused by reperfused myocardial infarction (MI) in rats by low-dose dobutamine (LDD) cardiovascular magnetic resonance (CMR) feature-tracking. Methods Nine sham rats and nine rats with 60-min myocardial ischemia followed by 48-h reperfusion were investigated using CMR, including T2*-mapping sequence and fast imaging with steady-state precession (FISP)–cine sequence. Another FISP–cine sequence was acquired after 2 min of dobutamine injection; the MI, IMH, and Non-MI (NMI) areas were identified. The values of peak radial strains (PRS) and peak circumferential strains (PCS) of the MI, IMH and NMI segments were acquired. The efficiency of PRS and PCS (EPRS and EPCS, respectively) were calculated on the basis of the time of every single heartbeat. Results The PRS, PCS, EPRS, and EPCS of the sham group increased after LDD injection. However, the PRS, PCS, EPRS, and EPCS of the IMH segment did not increase. Moreover, the PRS and PCS of the MI and NMI segments did not increase, but the EPRS and EPCS of these segments increased. The PRS, PCS, EPRS, and EPCS of the IMH segment were lower than those of the MI and NMI segments before and after LDD injection, but without a significant difference between MI segment and NMI segment before and after LDD injection. Conclusions LDD could help assess dysfunctions in segments with IMH, especially using the efficiency of strain. IMH was a crucial factor that decreased segmental movement and reserved function.

ObjectiveThe aim of this study was to evaluate the prognostic value for survival of parameters derived from intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in patients with nasopharyngeal carcinoma (NPC).MaterialsBaseline IVIM-DWI was performed on 97 newly diagnosed NPC patients in this prospective study. The relationships between the pretreatment IVIM-DWI parametric values (apparent diffusion coefficient (ADC), D, D*, and f) of the primary tumors and the patients’ 3-year survival were analyzed in 97 NPC patients who received chemoradiotherapy. The cutoff values of IVIM parameters for local relapse-free survival (LRFS) were identified by a non-parametric log-rank test. The local-regional relapse-free survival (LRRFS), LRFS, regional relapse-free survival (RRFS), distant metastasis-free survival (DMFS), progression-free survival (PFS), and overall survival (OS) rates were calculated by using the Kaplan–Meier method. A Cox proportional hazards model was used to explore the independent predictors for prognosis.ResultsThere were 97 participants (mean age, 48.4 ± 10.5 years; 65 men) analyzed. Non-parametric log-rank test results showed that the optimal cutoff values of ADC, D, D*, and f were 0.897 × 10−3 mm2/s, 0.699 × 10−3 mm2/s, 8.71 × 10−3 mm2/s, and 0.198%, respectively. According to the univariable analysis, the higher ADC group demonstrated significantly higher OS rates than the low ADC group (p = 0.036), the higher D group showed significantly higher LRFS and OS rates than the low D group (p = 0.028 and p = 0.017, respectively), and the higher D* group exhibited significantly higher LRFS and OS rates than the lower D* group (p = 0.001 and p = 0.002, respectively). Multivariable analyses indicated that ADC and D were the independent prognostic factors for LRFS (p = 0.041 and p = 0.037, respectively), D was an independent prognostic factor for LRRFS (p = 0.045), D* and f were the independent prognostic factors for OS (p = 0.019 and 0.029, respectively), and f acted was an independent prognostic factor for DMFS (p = 0.020).ConclusionsBaseline IVIM-DWI perfusion parameters ADC and D, together with diffusion parameter D*, could act as useful factors for predicting long-term outcomes and selecting high-risk patients with NPC.

AimsThis study aims to assess left ventricular (LV) function in hypertrophic cardiomyopathy (HCM) patients with preserved left ventricular ejection fraction (LVEF) by LV strain patterns based on cardiac magnetic resonance feature tracking (CMR-FT) and to explore the relationships between LV strain patterns and cardiac biomarkers in these patients, such as cardiac troponin (cTnT) and N-terminal prohormone of the brain natriuretic peptide (NT-proBNP).MethodsA total of 64 HCM patients with preserved LVEF and 33 healthy people were included in this study. All subjects underwent contrast-enhanced CMR, and all patients took blood tests for cTnT and NT-proBNP during hospitalization.ResultsDespite the absence of a significant difference in LVEF between HCM patients and healthy controls, almost all global and segmental strains in radial, circumferential, and longitudinal directions in the HCM group deteriorated significantly as compared to controls (p < 0.05). Moreover, some global and segmental strains correlated significantly with NT-proBNP and cTnT in HCM patients, and the best correlations were global radial strain (GRS) (r = −0.553, p < 0.001) and mid-ventricular radial strain (MRS) (r = −0.582, p < 0.001), respectively, with a moderate correlation. The receiver operating characteristic (ROC) results showed that among the LV deformation parameters, GRS [area under the curve (AUC), 0.76; sensitivity, 0.49; specificity, 1.00], MRS (AUC, 0.81; sensitivity, 0.77; specificity, 0.79) demonstrated greater diagnostic accuracy to predict elevated NT-proBNP, and abnormal cTnT, respectively. Their cut-off values were 21.17 and 20.94%, respectively. Finally, all global strains demonstrated moderate, good, and excellent intra- and inter-observer reproducibility.ConclusionLV strain patterns can be used to assess the subclinical cardiac function of HCM patients on the merit of being more sensitive than LVEF. In addition, LV strain patterns can detect serious HCM patients and may be helpful to non-invasively predict elevated NT-proBNP and cTnT.

PurposeThis study aims to investigate the role of sex and ovarian hormones in hippocampal damage and cognitive deficits and behavioral dysfunction in rats induced by chronic exposure to hypobaric hypoxia.MethodsSix-week-old male and female SD rats were housed for 3 months either in a real altitude (4,250 m) environment as the model of chronic hypobaric-hypoxia (CHH) or in a plain as controls. The animal behavioral and hippocampal neurons at subcellular, molecular, and ultrastructural levels were characterized after CHH exposure.ResultsAfter 3 months of CHH exposure, (1) male CHH rats’ serum testosterone level was lower than male controls’ whereas female CHH rats’ serum estradiol level was higher than female controls’; (2) Morris water maze test finds that male rats showed more learning and spatial memory deficits than female rats; (3) male rats showed more severe hippocampal damage, hippocampal inflammation, oxidative stress and decreased hippocampal integrity (neurogenesis and dendritic spine density) than female rats; (4) Western blot analysis shows that, compared with the male control group, in male CHH group’s hippocampus, expression of nNOS, HO-1, and Bax protein increased whereas that of Bcl-2 protein decreased; (5) Expression of PON2 protein in male rats (CHH and controls) was lower than female rats (CHH and controls). In addition, CHH exposure decreased the expression of PON2 protein in both male and female rats; (6) qPCR analysis reveals that CHH exposure reduced the gene expression of N-methyl-D-aspartate receptor NR2A and NR2B subunits in male rats’ hippocampus. In addition, compared with the sham CHH group, the expression level of PON2 protein decreased in the OVX-CHH group’s hippocampus whereas oxidative stress, neuroinflammation, and degeneration of hippocampal neurons increased in the OVX-CHH group’s hippocampus.ConclusionAfter CHH exposure, male rats were significantly more likely than female rats to develop hippocampal damage, hippocampal neuroinflammation, and cognitive decline and deficits, suggesting that sex and ovarian hormones were significantly involved in regulating the rats’ susceptibility to CHH exposure-induced hippocampal damage.

Based on the results discussed on the invariant planes in the known literature [Universe 2022, 8, 365] for the flat FLRW space-time universe model with ideal fluid under the gravity of f(R,T)=ξRα+ζ−T, this paper continues to describe the global dynamics of this model in the three-dimensional space containing infinity through dynamic system analysis. Moreover, the cosmological solutions of all the physical significance regions restricted by three invariant planes are also fully discussed.

Abstract Background Diffusion tensor imaging (DTI) is an effective method to identify subtle changes to normal-appearing white matter (WM). Here we analyzed the DTI data with other examinations, including motor evoked potentials (MEPs), histopathological images, and behavioral results, to reflect the lesion development in different degrees of spinal cord injury (SCI) in acute and subacute stages. Method Except for 2 Sprague -Dawley rats which died from the anesthesia accident, the rest 42 female rats were randomized into 3 groups: control group (n = 6), moderate group (n = 18), and severe group (n = 18). Moderate (a 50-g aneurysm clip with 0.4-mm thickness spacer) or severe (a 50-g aneurysm clip with no spacer) contusion SCI at T8 vertebrae was induced. Then the electrophysiological assessments via MEPs, behavioral deterioration via the Basso, Beattie, and Bresnaha (BBB) scores, DTI data, and histopathology examination were analyzed. Results In this study, we found that the damage of WM myelin, MEPs amplitude, BBB scores and the decreases in the values of fractional anisotropy (FA) and axial diffusivity (AD) were more obvious in the severe injury group than those of the moderate group. Additionally, the FA and AD values could identify the extent of SCI in subacute and early acute SCI respectively, which was reflected in a robust correlations with MEPs and BBB scores. While the values of radial diffusivity (RD) showed no significant changes. Conclusions Our data confirmed that DTI was a valuable in ex vivo imaging tool to identify damaged white matter tracts after graded SCI in rat, which may provide useful information for the early identification of the severity of SCI.

Abstract The global dynamics of a cosmological model based on Hořava–Lifshitz gravity in the presence of curvature is described by using the qualitative theory of differential equations.

ObjectiveWe used texture analysis and machine learning (ML) to classify small round cell malignant tumors (SRCMTs) and Non-SRCMTs of nasal and paranasal sinus on fat-suppressed T2 weighted imaging (Fs-T2WI).MaterialsPreoperative MRI scans of 164 patients from 1 January 2018 to 1 January 2021 diagnosed with SRCMTs and Non-SRCMTs were included in this study. A total of 271 features were extracted from each regions of interest. Datasets were randomly divided into two sets, including a training set (∼70%) and a test set (∼30%). The Pearson correlation coefficient (PCC) and principal component analysis (PCA) methods were performed to reduce dimensions, and the Analysis of Variance (ANOVA), Kruskal-Wallis (KW), and Recursive Feature Elimination (RFE) and Relief were performed for feature selections. Classifications were performed using 10 ML classifiers. Results were evaluated using a leave one out cross-validation analysis.ResultsWe compared the AUC of all pipelines on the validation dataset with FeAture Explorer (FAE) software. The pipeline using a PCC dimension reduction, relief feature selection, and gaussian process (GP) classifier yielded the highest area under the curve (AUC) using 15 features. When the “one-standard error” rule was used, FAE also produced a simpler model with 13 features, including S(5,-5)SumAverg, S(3,0)InvDfMom, Skewness, WavEnHL_s-3, Horzl_GlevNonU, Horzl_RLNonUni, 135dr_GlevNonU, WavEnLL_s-3, Teta4, Teta2, S(5,5)DifVarnc, Perc.01%, and WavEnLH_s-2. The AUCs of the training/validation/test datasets were 1.000/0.965/0.979, and the accuracies, sensitivities, and specificities were 0.890, 0.880, and 0.920, respectively. The best algorithm was GP whose AUCs of the training/validation/test datasets by the two-dimensional reduction methods and four feature selection methods were greater than approximately 0.800. Especially, the AUCs of different datasets were greater than approximately 0.900 using the PCC, RFE/Relief, and GP algorithms.ConclusionsWe demonstrated the feasibility of combining artificial intelligence and the radiomics from Fs-T2WI to differentially diagnose SRCMTs and Non-SRCMTs. This non-invasive approach could be very promising in clinical oncology.

Under the background of perfect fluid and flat Friedmann–Lemaître–Robertson–Walker (FLRW) space-time, this paper mainly describes the dynamics of the cosmological model constructed in f(R,T) gravity on three invariant planes, by using the singularity theory and Poincaré compactification in differential equations.

Abstract Objective Evaluation of the efficacy of adeno‐associated virus 2 mediated gene transfer of vascular endothelial growth factor Trap (AAV2‐VEGF‐Trap) alone or combination with paclitaxel in a mouse model of triple‐negative breast cancer (TNBC) using diffusion‐weighted magnetic resonance imaging (DW‐MRI) and in vivo fluorescence imaging. Materials and Methods Xenografted TNBC tumors were established by subcutaneous injection of MDA‐MB‐231 cells into nude mice. Tumors were treated with AAV2‐VEGF‐Trap, paclitaxel, AAV2‐VEGF‐Trap combined with paclitaxel and control. A 7.0‐Tesla magnetic resonance (MR) was used to obtain the apparent diffusion coefficient (ADC) values and ΔADC values. In vivo fluorescence imaging coupled with the optical imaging probe AngioSense680 EX was acquired to obtain average luminous intensity values. Immunohistochemical staining of tumor Ki‐67 and vascular endothelial cell marker antigen (CD31) were used to evaluate the effects on tumor proliferation and angiogenesis. Results The combination of AAV2‐VEGF‐Trap with paclitaxel exhibited greater tumor growth inhibition compared with the other groups. The ADC values in the paclitaxel group and the AAV2‐VEGF‐Trap in combination with paclitaxel group were significant greater compared with the control group, and the ΔADC values of all treatment groups were significantly increased compared with the control group on the 14th day after administration. Decreased microvessel density and luminous intensity in the treatment groups that contain AAV2‐VEGF‐Trap were observed. Reduced proliferation activity was noted in groups that contained paclitaxel. Conclusion AAV2‐VEGF‐Trap inhibits TNBC growth though inhibiting tumor neovascularization with a single intravenous injection, and AAV2‐VEGF‐Trap exhibits a synergistic effect when used in combination with paclitaxel for TNBC neoadjuvant therapy. In vivo fluorescence imaging can detect the anti‐angiogenesis effect of AAV2‐VEGF‐Trap early and noninvasively. DW‐MRI can longitudinally monitor the neoadjuvant efficacy of TNBC.

This paper addresses an analytic solution of the particles in a charged dilaton black hole based on the two-timing scale method from the perspective of dynamics. The constructed solution is surprisingly consistent with the “exact solution” in the numerical sense of the system. It can clearly reflect how the physical characteristics of the particle flow, such as the viscosity, absolute temperature, and thermodynamic pressure, affect the characteristics of the black hole. Additionally, we also discuss the geometric structure relationship between the critical temperature and the charge as well as the dilaton parameter when a charged dilaton black hole undergoes a phase transition. It is found that the critical temperature decreases with the increase of the charge for a given dilaton value. When the charge value is small, the critical temperature value will first decrease and then increase as the dilaton value increases. Conversely, the critical temperature value will always increase with the dilaton parameter.

Abstract Background Spontaneous T2DM in rhesus monkeys manifests as isolated diastolic dysfunction in the early stage of diabetic cardiomyopathy, similar to humans. Myocardial deformation measurements have emerged as a superior way to measure left ventricular (LV) function in the early stage of cardiac dysfunction, making it possible to further evaluate early-stage LV dysfunction in spontaneous T2DM rhesus monkeys. Methods Spontaneous T2DM rhesus monkeys with isolated diastolic dysfunction (T2DM-DD, n = 10) and corresponding nondiabetic healthy animals (ND, n = 9) were prospectively scanned for a CMR study. Circumferential and longitudinal peak systolic strain (Ecc, Ell), time to peak strain (tEcc, tEll) and peak diastolic strain rate (CSR, LSR) obtained from 2D/3D CMR-TT were compared with those obtained from CMR tagging separately. In addition, all CMR imaging protocols were performed twice in 9 ND animals to assess test-retest reproducibility. Results Compared with the ND group, the T2DM-DD monkeys demonstrated significantly impaired LV Ecc (− 10.63 ± 3.23 vs − 14.18 ± 3.19, p

Abstract Background We sought to compare diffusion tensor imaging (DTI) parameters in vivo and ex vivo in the brain and to explore the effects of radiofrequency coil and number of excitations on ex vivo DTI parameters. Methods Six Sprague–Dawley rat brains were used to obtain in vivo and ex vivo DTI maps with different coils and number of excitations. DTI parameters of white matter and grey matter including diffusivities, fractional anisotropy, and other dimensionless ratios (λ2/λ1, λ3/λ1, and λ2/λ3) were obtained from reconstruction maps. Comparisons of ex vivo signal-to-noise ratio with different coils and number of excitations were conducted. Results Diffusivities decreased significantly after fixation in all the selected white matter and grey matter regions of interest (all at p

This paper uses the Kolmogorov–Smirnov test to perform a fitting analysis on the mass data of Saturn’s regular moons and found that the lognormal distribution is its best-fitting distribution with an extremely high p-value of 0.9889. Moreover, novel dynamic equations for the variable-mass restricted three-body problem are established based on the newly discovered distribution of mass data, rather than the empirical Jeans’ law, and the Lindstedt–Poincaré perturbation method was used to give the approximate analytical periodic orbits near the Lagrangian point L3. Furthermore, this paper also discusses the influence of the three-body gravitational interaction parameter, the variable-mass parameter of the third body, and the scale parameter in the statistical results on the periodic orbits and the position of the Lagrangian point L3 through numerical simulation.

We illustrate the chaotic nature of the circular restricted three-body problem from the perspective of the bifurcation diagram with respect to the mass ratio parameter. Moreover, it is shown that when the frequency ratio in different directions of the classical problem is irrational, it has the quasiperiodic characteristics. In addition, a three-dimensional approximate solution to this problem under two time scales is proposed by using the multiple time scales method.

When the cosmological constant is non-zero, the dynamics of the cosmological model based on Hořava–Lifshitz gravity in a non-flat universe are characterized by using the qualitative theory of differential equations.

With the vast breakthrough brought by the Event Horizon Telescope, the theoretical analysis of various black holes has become more critical than ever. In this paper, the second-order asymptotic analytical solution of the charged dilaton black hole flow in the spinodal region is constructed from the perspective of dynamics by using the two-timing scale method. Through a numerical comparison with the original charged dilaton black hole system, it is found that the constructed analytical solution is highly consistent with the numerical solution. In addition, several quasi-periodic motions of the charged dilaton black hole flow are numerically obtained under different groups of irrational frequency ratios, and the phase portraits of the black hole flow with sufficiently small thermal parameter perturbation display good stability. Finally, the final evolution state of black hole flow over time is studied according to the obtained analytical solution. The results show that the smaller the integral constant of the system, the greater the periodicity of the black hole flow.

Against the background of a restricted three-body problem consisting of a supergiant eclipsing binary system, the two primaries are composed of a pair of bright oblate stars whose mass changes with time. The zero-velocity surface and curve of the problem are numerically studied to describe the third body’s motion area, and the corresponding five libration points are obtained. Moreover, the effect of small perturbations, Coriolis and centrifugal forces, radiative pressure, and the oblateness and mass parameters of the two primaries on the third body’s dynamic behavior is discussed through the bifurcation diagram. Furthermore, the second- and third-order approximate analytical periodic solutions around the collinear solution point L3 in two-dimensional plane and three-dimensional spaces are presented by using the Lindstedt-Poincaré perturbation method.

The nonlinear orbital dynamics of a class of the perturbed restricted three-body problem is studied. The two primaries considered here refer to the binary system HD 191408. The third particle moves under the gravity of the binary system, whose triaxial rate and radiation factor are also considered. Based on the dynamic governing equation of the third particle in the binary HD 191408 system, the motion state manifold is given. By plotting bifurcation diagrams of the system, the effects of various perturbation factors on the dynamic behavior of the third particle are discussed in detail. In addition, the relationship between the geometric configuration and the Jacobian constant is discussed by analyzing the zero-velocity surface and zero-velocity curve of the system. Then, using the Poincaré−Lindsted method and numerical simulation, the second- and third-order periodic orbits of the third particle around the collinear libration point in two- and three-dimensional spaces are analytically and numerically presented. This paper complements the results by Singh et al. [Singh et al., AMC, 2018]. It contains not only higher-order analytical periodic solutions in the vicinity of the collinear equilibrium points but also conducts extensive numerical research on the bifurcation of the binary system.

The bone marrow cavity (BMC) has recently been identified as an alternative site to the liver for islet transplantation. This study aimed to compare the BMC with the liver as an islet allotransplantation site in diabetic monkeys. Diabetes was induced in Rhesus monkeys using streptozocin, and the monkeys were then divided into the following three groups: Group1 (islets transplanted in the liver with immunosuppressant), Group 2 (islets transplanted in the tibial BMC), and Group 3 (islets transplanted in the tibial BMC with immunosuppressant). The C-peptide and blood glucose levels were preoperatively measured. An intravenous glucose tolerance test (IVGTT) was conducted to assess graft function, and complete blood cell counts were performed to assess cell population changes. Cytokine expression was measured using an enzyme-linked immune sorbent assay (ELISA) and MILLIPLEX. Five monkeys in Group 3 exhibited a significantly increased insulin-independent time compared with the other groups (Group 1: 78.2 ± 19.0 days; Group 2: 58.8 ± 17.0 days; Group 3: 189.6 ± 26.2 days) and demonstrated increases in plasma C-peptide 4 months after transplantation. The infusion procedure was not associated with adverse effects. Functional islets in the BMC were observed 225 days after transplantation using the dithizone (DTZ) and insulin/glucagon stains. Our results showed that allogeneic islets transplanted in the BMC of diabetic Rhesus monkeys remained alive and functional for a longer time than those transplanted in the liver. This study was the first successful demonstration of allogeneic islet engraftment in the BMC of non-human primates (NHPs).

Here, we report a new method using combined magnetic resonance (MR)–Photoacoustic (PA)–Thermoacoustic (TA) imaging techniques, and demonstrate its unique ability for in vivo cancer detection using tumor-bearing mice. Circular scanning TA and PA imaging systems were used to recover the dielectric and optical property distributions of three colon carcinoma bearing mice While a 7.0-T magnetic resonance imaging (MRI) unit with a mouse body volume coil was utilized for high resolution structural imaging of the same mice. Three plastic tubes filled with soybean sauce were used as fiducial markers for the co-registration of MR, PA and TA images. The resulting fused images provided both enhanced tumor margin and contrast relative to the surrounding normal tissues. In particular, some finger-like protrusions extending into the surrounding tissues were revealed in the MR/TA infused images. These results show that the tissue functional optical and dielectric properties provided by PA and TA images along with the anatomical structure by MRI in one picture make accurate tumor identification easier. This combined MR–PA–TA-imaging strategy has the potential to offer a clinically useful triple-modality tool for accurate cancer detection and for intraoperative surgical navigation.

The potential of using endothelial progenitor cells (EPCs) in novel anticancer therapy and the repair of vascular injury has been increasingly recognized. In the present study, EPCs were labeled with N-alkyl-polyethylenimine 2 kDa (PEI2k)-stabilized superparamagnetic iron oxide (SPIO) to facilitate magnetic resonance imaging (MRI) of EPCs in a mouse lung carcinoma xenograft model. EPCs derived from human peripheral blood were labeled with alkyl-PEI2k/SPIO. The viability and activity of labeled cells were evaluated using proliferation, migration, and tubulogenesis assays. Alkyl-PEI2k/SPIO-labeled EPCs were injected intravenously (group 1) or mixed and injected together with A549 cells subcutaneously (group 2) into groups of six mice with severe combined immunodeficiency. The labeling efficiency with alkyl-PEI2k/SPIO at 7 mg Fe/mL concentration was approximately 100%. Quantitative analysis of cellular iron was 6.062 ± 0.050 pg/cell. No significant effects on EPC proliferation, migration, or tubulogenesis were seen after labeling. Seventesla micro-MRI showed the presence of schistic or linear hypointense regions at the tumor margins starting from days 7 to 8 after EPC administration. This gradually extended into the inner tumor layers in group 1. In group 2, tumor growth was accompanied by dispersion of low-signal intensity regions inside the tumor. Iron-positive cells identified by Prussian blue dye were seen at the sites identified using MRI. Human CD31-positive cells and mouse CD31-positive cells were present in both groups. Labeling EPCs with alkyl-PEI2k/SPIO allows noninvasive magnetic resonance investigation of EPC involvement in tumor neovasculature and is associated with excellent biocompatibility and MRI sensitivity.

The blood-brain barrier (BBB) impedes entry of many drugs into the brain, limiting clinical efficacy. A safe and efficient method for reversibly increasing BBB permeability would greatly facilitate central nervous system (CNS) drug delivery and expand the range of possible therapeutics to include water soluble compounds, proteins, nucleotides, and other large molecules. We examined the effect of vascular endothelial growth factor (VEGF) on BBB permeability in Kunming (KM) mice. Human VEGF165 was administered to treatment groups at two concentrations (1.6 or 3.0 µg/mouse), while controls received equal-volume saline. Changes in BBB permeability were measured by parenchymal accumulation of the contrast agent Gd-DTPA as assessed by 7 T magnetic resonance imaging (MRI). Mice were then injected with Evans blue, sacrificed 0.5 h later, and perfused transcardially. Brains were removed, fixed, and sectioned for histological study. Both VEGF groups exhibited a significantly greater signal intensity from the cerebral cortex and basal ganglia than controls (P

Rho family GTPases are critical regulators of many important cellular processes and the dysregulation of their activities is implicated in a variety of human diseases including oncogenesis and propagation of malignancy. The traditional methods, such as "pull-down" or two-hybrid procedures, are poorly suited to dynamically evaluate the activity of Rho GTPases, especially in living mammalian cells. To provide a novel alternative approach to analyzing Rho GTPase-associated signaling pathways in vivo, we developed a series of bioluminescent biosensors based on the genetically engineered firefly luciferase. These split-luciferase-based biosensors enable non-invasive visualization and quantification of the activity of Rho GTPases in living subjects. The strategy is to reasonably split the gene of firefly luciferase protein into two inactive fragments and then respectively fuse the two fragments to Rho GTPase and the GTPase-binding domain (GBD) of the specific effector. Upon Rho GTPase interacting with the binding domain in a GTP-dependent manner, these two luciferase fragments are brought into close proximity, leading to luciferase reconstitution and photon production in the presence of the substrate. Using these bimolecular luminescence complementation (BiLC) biosensors, we successfully visualized and quantified the activities of the three best characterized Rho GTPases by measuring the luminescence in living cells. We also experimentally investigated the sensitivity of these Rho GTPase biosensors to upstream regulatory proteins and extracellular ligands without lysing cells and doing labor-intensive works. By virtue of the unique functional characteristics of bioluminescence imaging, the BiLC-based biosensors provide an enormous potential for in vivo imaging of Rho GTPase signaling pathways and high-throughput screening of therapeutic drugs targeted to Rho GTPases and (or) upstream molecules in the near future.

To enrich our understanding of the mechanism of tumor lymphatic metastasis, we developed a model system for tracking metastatic tumor cells in the lymphatic system with cellular magnetic resonance imaging (MRI) in live mice to observe the interaction between tumor cells and the lymphatic system. Nude mice were inoculated subcutaneously with superparamagnetic iron oxide (SPIO)-labeled and unlabeled LOVO cells in the foot pad, groin, or axillary area. Serial 7 T MRI of the tumors and surrounding regions was performed in the following 2 weeks. After imaging, tumor tissues and regional lymph nodes were collected and subjected to immunohistologic analysis. T 2 /T 2 *-weighted MRIs showed the primary tumor growth and the draining lymphatic architecture, as well as the SPIO-labeled tumor cells metastasized into the regional lymph node at 8 days. MRIs also revealed information on sentinel lymph node mapping with high-resolution anatomic information. Histologic findings confirmed the in vivo MRI results and revealed lymphangiogenesis, angiogenesis, infiltration of macrophages, and expression of vascular endothelial growth factor C in tumor and draining lymph nodes as well. This technology provides a powerful tool for tracking SPIO-labeled cancer cells in the lymphatics by cellular MRI. There was a close relationship between tumor lymphatic metastasis and lymphangiogenesis.