Discrete unified gas-kinetic wave-particle method for flows in all flow regimes.

This work proposes a discrete unified gas-kinetic wave-particle (DUGKWP) method for simulation of flows in all flow regimes. Unlike the discrete velocity method (DVM) and the direct simulation Monte Carlo (DSMC) method which solve the governing equations by either the deterministic method or the stochastic method, the DUGKWP combines the advantages of these two methods. In the DUGKWP, the information of microscopic particles as well as macroscopic flow variables are both evolved. Specifically, the microscopic particles are updated by the free-transport and resampling processes, while the macroscopic flow properties are evolved via solving the macroscopic governing equations of conservation laws with the finite volume method. According to the discrete characteristic solution to the Boltzmann-BGK equation utilized in the DUGKWP, in the highly rarefied flow regime, the motion of microscopic particles greatly determines the fluxes for the macroscopic governing equations. Conversely, for the continuum flow, no microscopic particle exists in the computational domain and the DUGKWP is degraded to the Navier-Stokes solver. Numerical studies validate that the DUGKWP can accurately predict the flow properties in all flow regimes. Furthermore, compared with the deterministic method, the DUGKWP enjoys superior efficiency with less memory consumption for both high-speed rarefied flows and flows close to the continuum regime.

[Prevalence of mountain-zoonotic type visceral leishmaniasis in Yangquan City of Shanxi Province from 2015 to 2020].

OBJECTIVE: To investigate the prevalence of mountain-type zoonotic visceral leishmaniasis (MT-ZVL) in Yangquan City, Shanxi Province from 2015 to 2020, so as to provide the scientific evidence for formulating the MT-ZVL control strategy. METHODS: The epidemiological data pertaining to MT-ZVL cases in Yangquan City from 2015 to 2020 were collected and descriptively analyzed. A Joinpoint regression model was created to analyze the trend in the MT-ZVL incidence in Yangquan City from 2015 to 2020 using annual percent change (APC). The sandflies surveillance data and the prevalence of Leishmania infections in dogs were collected in Yangquan City in 2020, and the regional distribution of sandflies density and sero-prevalence of Leishmania infections in dogs were calculated. In addition, the associations of sandflies density and sero-prevalence of Leishmania infections in dogs with the incidence of human MT-ZVL were examined using the linear correlation analysis. RESULTS: A total of 162 MT-ZVL cases were reported in Yangquan City, Shanxi Province from 2015 to 2020, with annual mean incidence of 1.9/105, and there were 4, 7, 16, 27, 33 cases and 75 cases with MT-ZVL reported from 2015 to 2020, appearing a tendency towards a rapid rise (APC = 72.79%, t = 11.10, P < 0.01). MT-ZVL cases were reported across the five counties (districts) of Yangquan City, and the cases predominantly occurred in Jiaoqu District (35.2%, 57/162) and Pingding County (33.3%, 54/162). MT-ZVL cases were predominantly detected in residents at ages of 15 years and older (71.6%, 116/162) and at ages of 0 to 2 years (22.2%, 36/162), with farmers (37.4%, 61/162) and diaspora children (24.5%, 40/162) as predominant occupations. The mean density of Phlebotomus chinensis was 6.3 sandflies per trap per night in Yangquan City from during the period from May to September, 2020, with the highest density observed in Jiaoqu District (12.6 sandflies per trap per night) and the lowest in Yuxian County (1.1 sandflies per trap per night), and there was a region-specific mean density of Ph. chinensis in Yangquan City (H = 17.282, P < 0.01). The sero-prevalence of serum anti-Leishmania antibody was 7.4% (2 996/40 573) in domestic dogs in Yangquan City, with the highest sero-prevalence seen in Jiaoqu District (16.6%, 1 444/8 677), and the lowest in Yuxian County (2.3%, 266/11 501), and there was a region-specific sero-prevalence rate of anti-Leishmania antibody in domestic dogs in Yangquan City (χ2 = 1 753.74, P < 0.01). The sero-prevalence of anti-Leishmania antibody was significantly higher in stray dogs (20.0%, 159/794) than in domestic dogs (χ2 = 176.63, P < 0.01). In addition, there were significant associations among the sandflies density, sero-prevalence of anti-Leishmania antibody in domestic dogs and the incidence of human MT-ZVL (r = 0.832 to 0.870, all P values < 0.05). CONCLUSIONS: The prevalence of MT-ZVL appeared a tendency towards a rapid rise in Yangquan City from 2015 to 2020, and systematic interventions are urgently needed for MT-ZVL control.

[First report of invasive Pomacea snails in Shandong Province].

OBJECTIVE: To characterize the species of invasive Pomacea snails that were discovered for the first time in Shandong Province. METHODS: Pomacea snails samples were collected in the field of Jining City, Shandong Province on October 2021 for morphological identification. Pomacea snails were randomly sampled and genomic DNA was extracted from foot muscle tissues of Pomacea snails for multiplex PCR amplification. The PCR amplification product was sequenced. Then, the sequence was aligned and a phylogenetic tree was created using the software MegAlign 7.1.0. In addition, Angiostongylus cantonensis infection was detected in Pomacea snails with the lung microscopy. RESULTS: A total of 104 living Pomacea snails were collected, and all were characterized as Pomacea spp. based on morphological features. Of 12 randomly selected adult Pomacea snails, multiplex PCR assay and sequencing identified eleven snails as P. canaliculata and one as P. maculata. No A. cantonensis infection was detected in 104 Pomacea snails. CONCLUSIONS: This is the first report of invasive Pomacea snails in Shandong Province, where P. canaliculata and P. maculata are found.

Development of explicit formulations of G45-based gas kinetic scheme for simulation of continuum and rarefied flows.

In this work, the explicit formulations of the Grad's distribution function for the 45 moments (G45)-based gas kinetic scheme (GKS) are presented. Similar to the G13 function-based gas kinetic scheme (G13-GKS), G45-GKS simulates flows from the continuum regime to the rarefied regime by solving the macroscopic governing equations based on the conservation laws, which are widely used in conventional Navier-Stokes solver. These macroscopic governing equations are discretized by the finite volume method, where the numerical fluxes are evaluated by the local solution to the Boltzmann equation. The initial distribution function is reconstructed by the G45 distribution function, which is a higher order truncation of the Hermite expansion of distribution function compared with the G13 distribution function. Such high order truncation of Hermite expansion helps the present solver to achieve a better accuracy than G13-GKS. Moreover, the reconstruction of distribution function makes the development of explicit formulations of numerical fluxes feasible, and the evolution of the distribution function, which is the main reason why the discrete velocity method is expensive, is avoided. Several numerical experiments are performed to examine the accuracy of G45-GKS. Results show that the accuracy of the present solver for almost all flow problems is much better than G13-GKS. Moreover, some typical rarefied effects, such as the direction of heat flux without temperature gradients and thermal creep flow, can be well captured by the present solver.

Variant of gas kinetic flux solver for flows beyond Navier-Stokes level.

In this paper, a variant of gas kinetic flux solver (GKFS) is presented for simulation of flows beyond the Navier-Stokes (NS) level. The method retains the framework of GKFS and reconstructs the numerical fluxes by the moments of distribution function at the cell interface, which is given from the local solution of the Boltzmann equation. In the conventional GKFS, the first-order Chapman-Enskog (CE) expansion is utilized to approximate the initial distribution function. By using the differential chain rule, it was found that the CE expansion form could be linked to the stress tensor and the heat flux. For flows in the NS level, the stress tensor and heat flux can be simply calculated from the linearized constitutive relationship and Fourier's law, respectively. However, for flows beyond the NS level, due to the strong nonequilibrium effect, the linearized constitutive relationship and Fourier's law are insufficient to predict the stress tensor and the heat flux. To overcome this difficulty, this paper introduces correction terms to the stress tensor and heat flux in the initial distribution function. These correction terms will take effect in the strong nonequilibrium region for flows beyond the NS level. To avoid finding complex expressions or solving complicated partial differential equations for the correction terms, a simple and iterative procedure is proposed to update the correction terms based on the framework of GKFS. The proposed method is validated by three benchmark cases which cover the flow from the continuum regime to the transition regime. Numerical results show that the present solver can provide accurate solution in the continuum regime. It is indeed the correction terms that take effect in the strong nonequilibrium region for flows beyond the NS level, which enables the present solver to capture the nonequilibrium phenomenon with reasonable accuracy for rarefied flows at moderate Knudsen number.

Efficient high-order radial basis-function-based differential quadrature-finite volume method for incompressible flows on unstructured grids.

This paper presents an efficient high-order radial basis-function-based differential quadrature-finite volume method for incompressible flows on unstructured grids. In this method, a high-order polynomial based on the Taylor series expansion is applied within each control cell to approximate the solution. The derivatives in the Taylor series expansion are approximated by the mesh-free radial basis-function-based differential quadrature method. The recently proposed lattice Boltzmann flux solver is applied to simultaneously evaluate the inviscid and viscous fluxes at the cell interface by the local solution of the lattice Boltzmann equation. In the present high-order method, a premultiplied coefficient matrix appears in the time-dependent term, reflecting the implicit nature. The implicit time-marching techniques, i.e., the lower-upper symmetric Gauss-Seidel and the explicit first stage, singly diagonally implicit Runge-Kutta schemes, are incorporated to efficiently solve the resultant ordinary differential equations. Several numerical examples are tested to validate the accuracy, efficiency, and robustness of the present method on unstructured grids. Compared with the k-exact method, the present method enjoys higher accuracy and better computational efficiency.

Gas kinetic flux solver based high-order finite-volume method for simulation of two-dimensional compressible flows.

In this work, a high-order gas kinetic flux solver (GKFS) is developed for simulation of two-dimensional (2D) compressible flows. Different from the conventional gas kinetic scheme, which uses the local integral solution to the Boltzmann equation to reconstruct the numerical fluxes of macroscopic governing equations, the GKFS evaluates the numerical fluxes by the local asymptotic solution to the Boltzmann equation. This local asymptotic solution consists of the equilibrium distribution function and its substantial derivative at the cell interface. To achieve high-order accuracy in the simulation, the substantial derivative is discretized by a difference scheme with second-order accuracy in time and fourth-order accuracy in space, which results in a polynomial of the equilibrium distribution function at different locations and time levels. The Taylor series expansion is then introduced to simplify this polynomial. As a result, a simple high-order accurate local asymptotic solution to the Boltzmann equation is obtained and the numerical fluxes of macroscopic governing equations are given explicitly. A series of numerical examples are presented to validate the accuracy and capability of the developed high-order GKFS. Numerical results demonstrate that the high-order GKFS can achieve the desired accuracy on both the quadrilateral mesh and the triangular mesh and it outperforms the second-order counterpart.

Phase-field-simplified lattice Boltzmann method for modeling solid-liquid phase change.

This article proposes a phase-field-simplified lattice Boltzmann method (PF-SLBM) for modeling solid-liquid phase change problems within a pure material. The PF-SLBM consolidates the simplified lattice Boltzmann method (SLBM) as the flow solver and the phase-field method as the interface tracking algorithm. Compared with conventional lattice Boltzmann modelings, the SLBM shows advantages in memory cost, boundary treatment, and numerical stability, and thus is more suitable for the present topic which includes complex flow patterns and fluid-solid boundaries. In contrast to the sharp interface approach, the phase-field method utilized in this work represents a diffuse interface strategy and is more flexible in describing complicated fluid-solid interfaces. Through abundant benchmark tests, comprehensive validations of the accuracy, stability, and boundary treatment of the proposed PF-SLBM are carried out. The method is then applied to the simulations of partially melted or frozen cavities, which sheds light on the potential of the PF-SLBM in resolving practical problems.

Zika virus transmission via breast milk in suckling mice.

OBJECTIVES: Infectious Zika viral particles were detected in human milk; however, whether they can be transmitted via breastfeeding remains unknown, so our objective was to clarify this. METHODS: Here, in a natural breastfeeding model, wild-type (C57Bl/6; WT) or interferon α/ß (IFNα/ß) receptor-deficient (A129; KO) murine dams on day 1 post-delivery were infected with Zika virus (ZIKV) intraperitoneally, and the neonates were suckled. In a novel artificial feeding model, WT suckling mice at 1 day old were fed with ZIKV alone or ZIKV and human breast milk mixtures. Thereafter, the virus distribution, clinical progression and neuropathology in the WT or KO neonates were characterized to evaluate the risk of ZIKV transmission through breast milk. RESULTS: In natural breastfeeding, viral RNAs (8/8) and infectious viral particles (7/8) were extensively present in the mammary glands of KO dams. All tested KO neonates (5/5), and none of WT neonates (0/9), were infected with ZIKV. In artificial feeding, 100% of the WT neonates (two groups, 12/12 and 16/16) were infected and developed some signs of neurodegeneration. ZIKV tended to seed and accumulate in the lungs and were subsequently disseminated to other tissues in both 16 naturally suckled and 19 artificially fed infected neonates. As human breast milk was mixed with ZIKV and fed to WT neonates, 45% individuals (9/20) were infected; in the infected neonates, the viral spread to the brain was delayed, and the clinical outcomes were alleviated. CONCLUSIONS: These results demonstrated that suckling mice can be infected with ZIKV through suckling, and breast milk has potential antiviral activity, inhibiting ZIKV infection.

Three-dimensional lattice Boltzmann flux solver for simulation of fluid-solid conjugate heat transfer problems with curved boundary.

A three-dimensional (3D) lattice Boltzmann flux solver is presented in this work for simulation of fluid-solid conjugate heat transfer problems with a curved boundary. In this scheme, the macroscopic governing equations for mass, momentum, and energy conservation are discretized by the finite-volume method, and the numerical fluxes at the cell interface are reconstructed by the local solution of lattice Boltzmann equation. For solving the 3D fluid-solid conjugate heat transfer problems, the density distribution function (D3Q15 model) is utilized to compute the numerical fluxes of continuity and momentum equations, and the total enthalpy distribution function (D3Q7 model) is introduced to calculate the numerical flux of the energy equation. The connections between the macroscopic fluxes and the local solution of the lattice Boltzmann equation are provided by the Chapman-Enskog expansion analysis. As compared with the lattice Boltzmann method, in which the time step and grid spacing are correlated, the local solution of the lattice Boltzmann equation at each cell interface used in the present scheme is independent of each other. As a result, the drawback of the tie-up between the time step and grid spacing can be effectively removed and the developed method applies very well to nonuniform mesh and curved boundaries. To validate the performance of the developed method, the steady and unsteady natural convection in a finned 3D cavity and in a finned 3D annulus are simulated. Numerical results showed that the present scheme can effectively solve the 3D conjugate heat transfer problems with a curved boundary.

[Correlation between DCE-MRI quantitative perfusion histogram parameters, apparent diffusion coefficient and Ki-67 in different pathological types of lung cancer].

Objective: To explore the efficacy of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) histogram molecular imaging index, apparent diffusion coefficient (ADC) in different types of lung cancer and explore their correlation with Ki-67. Methods: A total of 33 cases of lung cancer patients confirmed by pathology in Shaoxing People's Hospital from March 2017 to March 2018 were collected, 28 males and 5 females aged 50-85 years old, including 15 cases of squamous cell carcinoma, 12 cases of adenocarcinoma, and 6 cases of small cell carcinoma. All patients performed DCE-MRI and DWI imaging within one week before surgery or puncture. ADC values, DCE-MRI quantitative perfusion parameters by histogram metrics analysis (mean value, skewness, kurtosis, uniformity, entropy, energy, quantile) of K(trans), K(ep), V(e), and V(p) were then collected. Ki-67 expression in lung cancer tissue was detected by immunohistochemical method. One-way analysis of variance and least significant difference were used to compare the differences among the parameters of the three groups which were normal distribution and equal variances, while Kruskal-Walls test and Mann-Whitney U test were used to compare the parameters that did not conform to normal distribution or variance. Pearson correlation analysis was used to compare the correlations between quantitative perfusion histogram parameters, ADC values and immunohistochemical scores of Ki-67. Results: The Ki-67 count in small cell lung cancer(458±82, P=0.011) and squamous cell carcinoma(355±277, P=0.034)were significantly higher than that in adenocarcinoma (168±164). The correlation analysis showed that there was a significant negative correlation between ADC values and Ki-67 (P=0.018, r=-0.416). And V(e) (Q5, Q10) was negatively related to Ki-67 (P=0.017, r=-0.420; P=0.040, r=-0.366). In squamous cell carcinoma patients, V(e) (homogeneity) was significantly negatively correlated with the expression of Ki-67 (P=0.033, r=-0.570). K(trans)(homogeneity) and V(e) (homogeneity, Q5, Q10, Q25) were significantly positively correlated with ADC values (P value from 0.001 to 0.035, r value from 0.545 to 0.765). Conclusion: DCE-MRI quantitative perfusion histogram parameters, ADC value can evaluate the lung cancer cell proliferation activity in different pathological types.

High-order least-square-based finite-difference-finite-volume method for simulation of incompressible thermal flows on arbitrary grids.

In this work, a high-order (HO) least-square-based finite difference-finite volume (LSFD-FV) method together with thermal lattice Boltzmann flux solver (TLBFS) is presented for simulation of two-dimensional (2D) incompressible thermal flows on arbitrary grids. In the present method, a HO polynomial based on Taylor series expansion is applied within each control cell, where the unknown spatial derivatives at each cell center are approximated by least-square-based finite difference (LSFD) scheme. Then the recently developed TLBFS is applied to evaluate the convective and diffusive fluxes simultaneously at the cell interface by local reconstruction of thermal lattice Boltzmann solutions of the density and internal energy distribution functions. The present HO LSFD-FV method is verified and validated by 2D incompressible heat transfer problems. Numerical results indicate that the present method can be effectively and flexibly applied to solve thermal flow problems with curved boundaries on arbitrary grids. Compared with the conventional low-order finite volume method, higher efficiency and lower memory cost make the present HO method more promising for practical thermal flow problems.

[The correlation between the cell density of local advanced lung cancer tumor and the ADC value of 3.0 T MRI diffusion weighted imaging].

Objective: To investigate the correlation between tumorous cellular density (TCD) and apparent diffusion coefficient (ADC) of 3.0 T magnetic resonance diffusion weighted imaging (DWI) in local advanced lung cancer. Methods: From January 2015 to December 2017, a total of 59 patients with locally advanced lung cancer confirmed by pathology in Shaoxing People's Hospital who underwent DWI by 3.0 T magnetic resonance imaging were included.The ADC and TCD values of tumor were measured. The difference and correlation between ADC value and TCD in lung cancer were analyzed. Results: Among 59 lung cancer cases who were examined with DWI, 45 cases of TCD were obtained. Statistical analysis showed that the ADC value of small cell lung cancer (SCLC) was significantly higher than that of squamous cell carcinoma (P=0.011)and adenocarcinoma (P=0.004). TCD of small cell carcinoma was significantly higher than that of squamous cell carcinoma (P=0.007) and adenocarcinoma (P<0.01). There was no statistical difference in ADC value and TCD between squamous cell carcinoma and adenocarcinoma (all P>0.05). There was negative correlation between the ADC value and TCD in lung cancer (P=0.001, r=-0.534). Conclusions: DWI is not only beneficial to distinguish SCLC from squamous cell carcinoma and adenocarcinoma, but also can indirectly reflect the tumorous cellular density.It can provide a basis for monitoring the therapeutic effect of clinical lung cancer.

LncRNA MEG3 participates in neuronal cell injury induced by subarachnoid hemorrhage via inhibiting the Pi3k/Akt pathway.

OBJECTIVE: To explore the effect of LncRNA MEG3 in the subarachnoid hemorrhage (SAH) and its underlying mechanism. PATIENTS AND METHODS: The expressions of lncRNA MEG3 in SAH patients and animal model were detected by quantitative real-time PCR (qRT-PCR). After LncRNA MEG3 was overexpressed in neurons by lentivirus, viability and apoptosis abilities were detected by cell counting kit-8 (CCK-8) assay, flow cytometry, and TUNEL assay, respectively. The apoptosis-related genes and Pi3k/Akt pathway-related proteins were further detected by a Western blot. RESULTS: The expressions of lncRNA MEG3 in SAH patients were remarkably higher than normal controls, which were positively correlated with SAH severity. After lncRNA MEG3 overexpression, neuronal cell activity was decreased and cell apoptosis was increased. Moreover, the expressions of Bax, p53, and cleaved Caspase-3 were increased, whereas the expression of Bcl-2 and Pi3k/Akt pathway-related proteins were decreased after lncRNA MEG3 overexpression. CONCLUSIONS: LncRNA MEG3 is up-regulated in SAH, which may promote SAH-induced neuronal cell injury via inhibition of the Pi3k/Akt pathway.

Development of an efficient gas kinetic scheme for simulation of two-dimensional incompressible thermal flows.

In this work, an efficient gas kinetic scheme is presented for simulation of two-dimensional incompressible thermal flows. In the scheme, the macroscopic governing equations for mass, momentum, and energy conservation are discretized by the finite volume method and the numerical fluxes at the cell interface are reconstructed by the local solution of the Boltzmann equation. To compute these fluxes, two distribution functions are involved. One is the circular function, which is used to calculate the numerical fluxes of mass and momentum equations. Due to the incompressible limit, the circle at the cell interface can be approximately considered to be symmetric so that the expressions for the conservative variables and numerical fluxes at the cell interface can be given explicitly and concisely. Another one is the D2Q4 model, which is utilized to compute the numerical flux of the energy equation. By following the process for derivation of numerical fluxes of mass and momentum equations, the numerical flux of the energy equation can also be given explicitly. The accuracy, efficiency, and stability of the present scheme are validated by simulating several thermal flow problems. Numerical results showed that the present scheme can provide accurate numerical results for incompressible thermal flows at a wide range of Rayleigh numbers with less computational cost than that needed by the thermal lattice Boltzmann flux solver (TLBFS), which has been proven to be more efficient than the thermal lattice Boltzmann method (TLBM).

[The protective effect of N-acetylcysteine on acute lung injury induced by PFIB inhalation].

Objective: To study the protective effect of N-acetylcysteine on acute lung injury induced by PFIB inhalation and its mechanism. Methods: Survival experiment: 48 male ICR (CD-1) mice were randomly divided into 4 groups, i. e., PFIB control group, NAC prevention group, NAC treatment group, and NAC prevention + treatment group, each group contains 12 animals. The mice of PFIB C group were exposed to PFIB without any treatment. The mice of NAC P group were exposed to PFIB 30min after NAC administration. The mice of NAC T group were exposed to PFIB 1h before NAC administration, The mice of NAC P+T group were administrated with NAC twice (30 min before and 1h after PFIB inhalation) . 150 mg/kg NAC was given by each time. The 7 days survival rate of mice after lethal dose PFIB exposure was observed. 18 male Wistar rats were randomly divided into 3 groups i.e., normal control group (N-C) , PFIB control group (PFIB-C) and NAC prevention group (NAC-P) , with each group contains 6 animals in the second experiment. The rats of N-C group received no treatment. The rats of NAC-P group and PFIB-C group were exposed to PFIB 30min after treatment of NAC (420 mg/Kg, i.p.) and saline, respectively. The respiratory functions of animals were tested before and 24 h after PFIB inhalation. The arterial blood gas was analyzed after rats were anesthetized 24 hours post sublethal dose PFIB exposure. Then samples of BALF, plasma and lung tissue were collected. Wet lung/body weight ratio, protein and phospholipid content in BALF, and T-SOD, GSH, GSH-Px in plasma and lung tissue were measured. The expression of Peroxiredoxin 2 was detected by Westernblot assay. Results: NAC prevention can significantly improve the survival of mice exposed to a lethal dose PFIB while NAC treatment is ineffective. Severe lung edema was observed in rats 24 h after PFIB exposure. Compared to N-C group, the wet lung/body weight ratio, protein and phospholipid content in BALF, and respiratory rate of PFIB control group all increased significantly (P<0.01) . The arterial oxygen partial pressure (PaO(2)) reduced significantly (P<0.05) . The GSH-Px activity in lung tissue reduced significantly (P<0.01) while the expression of Peroxiredoxin 2 increased significantly (P<0.01) . NAC prophylaxis significantly reduced the wet lung/body weight ratio, protein and phospholipid content in BALF, respiratory rate of rats exposed to PFIB (P<0.01) . Compared with PFIB-C group, the PaO(2) (P<0.05) and the activity of GSH-Px (P<0.01) and the expression of Peroxiredoxin 2 in lung tissue (P<0.01) were increased significantly. Conclusion: Acute lung injury induced by PFIB inhalation is related to oxidative stress caused by the stimulation to lung. induced and pulmonary subjected to stimulate the generation of exposure, NAC prevention can regulation of the redox system in lung tissue and protect target organ of the treated animals effectively.

[Prediction of occult carcinoma in contralateral nodules based on the ultrasonic features of unilateral papillary thyroid carcinoma].

Objective: To investigate the occurrence of occult carcinoma in contralateral lobes based on the ultrasonic features of unilateral papillary thyroid carcinoma. Methods: The study included 202 consecutives cases of unilateral papillary thyroid carcinoma with benign nodules in the contralateral lobe identified by preoperative ultrasound or fine-needle aspiration from June 2014 to December 2015. All patients received total thyroidectomies, and with postoperative pathological examination they were divided into two groups, one including 60 cases with positive occult cancer and another one consisting of 142 cases with negative occult cancer. Univariate and multivariate analyses were performed to analyze the sonographic features of unilateral papillary thyroid carcinoma relevant to the occurrence of occult carcinoma in the contralateral nodules. Results: Univariate analysis indicated occult carcinoma in the contralateral lobes was associated with Hashimoto's thyroiditis(χ(2)=3.955, P=0.047), unclear border (χ(2)=4.375, P=0.036)and multifocality in the ipsilateral(χ(2)=7.375, P=0.007), but not with tumors maximum size, location, A/T, shape, internal structure, internal echo, acoustic halo, calcification, capsular invasion and blood flow signal in the lobe with carcinoma on another side. Multivariate analysis showed unclear border (OR=2.727, P=0.010) and multifocality in the ipsilateral(OR=2.807, P=0.005)of carcinoma were independent predictive factor for contralateral occult PTC. Conclusions: Unclear border and multifocality of PTC in the ipsilateral were closely relevant to the occurrence of occult carcinoma in the contralateral nodules.

[Application on the quantitative perfusion parameters of dynamic contrast-enhanced MRI in the pathological subtype of uterine leiomyoma].

Objective: To analyze the value of the quantitative perfusion parameters of dynamic contrast-enhanced MRI(DCE-MRI) in the pathological subtype of uterine leiomyoma. Methods: A total of 35 cases of uterine leiomyoma confirmed by surgery and pathology were retrospectively analyzed in Shaoxing People's Hospital from October 2015 to May 2016.All cases underwent DCE-MRI. Quantitative perfusion parameters were prospectively measured and analyzed, including transfer constant (K(trans)) , efflux rate constant (K(ep)), extravascular extracellular space volume ratio (V(e)), blood plasma volume ratio (V(p)), permeability surface area product (PS) and plasma flow (F(p)) , using signal-input two-compartment tracer kinetic models (Extended Tofts model and Exchange model) in 35 leiomyoma cases.After the operation, the 35 cases were divided into three groups according to the pathological classfication , the ordinary, the cellular and the degeneration type.To analyze the differences among the three groups about the quantitative perfusion parameters of uterine leiomyoma. Compared with the gold standard of pathological findings, the ROC curves were drawn to evaluate the diagnostic efficacy of different quantitative perfusion parameters. Results: In the ordinary, cellular and degeneration type of uterine leiomyoma, K(trans) value were respectively(0.684±0.341), (1.897±0.458), (0.554±0.514)/min; K(ep) were respectively(1.004±0.685), (2.362±1.001), (1.274±1.093)/min; V(e) were respectively 0.789%±0.186%, 0.806%±0.203%, 0.537%±0.314%; V(p) were respectively 0.145%±0.196%, 0.502%±0.338%, 0.062%±0.106% and F(p) were respectively(0.792±0.461), (2.426±0.509), (0.628±0.551)ml/min.Among three groups, the value of K(trans), K(ep), V(e), V(p) and F(p) had statistical difference(all P<0.05), the value of PS didn't have statistical difference. The value of K(trans), K(ep), V(p) and F(p) in cellular type were higher than the ordinary type(all P<0.01); the value of K(trans), V(p) and F(p) in cellular type were higher than the degeneration type(all P<0.01); the value of V(e) in ordinary type was higher than the degeneration type(P<0.05). The area under ROC curve was 0.981 for K(trans), 0.904 for K(ep), 0.622 for V(e), 0.840 for V(p) and 0.994 for F(p). Conclusion: The quantitative perfusion parameters of DCE-MRI , especially the value of K(trans), K(ep), V(p) and F(p) have a great diagnostic efficacy in the pathological classfication of uterine leiomyoma which will become a predictive factor of pathological classfication in uterine leiomyoma.