[Preliminary study of whole-tumor volume analysis of mono-exponential and intravoxel incoherent motion models in the preoperative histologic grading of hepatocellular carcinoma].

Objective: To investigate the diagnostic performance of whole-tumor volume analysis of mono-exponential and intravoxel incoherent motion (IVIM)parameters in the preoperative grading of hepatocellular carcinoma (HCC). Methods: A total of 106 patients who undewent parital hepatectomy were prospectively enrolled and underwent with routine MR and IVIM examination.112 HCCs were confirmed by the surgical pathology.The original images of IVIM were imported into the GE AW 4.6 workstation.Two independent radiologist who were blinded to the histopathological results analyzed the data.Freehand ROI was used to cover the whole tumor volume, ADC, ADC(slow), ADC(fast) and f was calculated.Intra-class correlation coefficient (ICC) was used to evaluate the inter-observer agreement, One-way ANOVA and Kruskal-Wallis sign rank test were used to evaluate the difference of these parameters in grading HCC, Spearman correlation analysis was used to determine the correlation between these parameters and histologic grade, receiver operating characteristics (ROC) curves were performed to evaluate the diagnostic performance. Results: ICC value of ADC, ADC(slow), ADC(fast) and f were 0.948, 0.966, 0.901 and 0.940, respectively.Statistical significances were obtained from the ADC(slow)(R1: χ(2)=74.403, P<0.001; R2: F=44.973, P<0.001) and ADC (R1: χ(2)=52.987, P<0.001; R2: F=30.851, P<0.001) in grading HCC.Between the multiple-comparison in grading HCC, the ADC(slow) and ADC (except for E-S 3 and 4, R1: P=0.134; R2: P=0.069) also demonstrated a statistical significant difference (all P<0.05). Area under curve (AUC) value of two radiologists for ADC(slow) were 0.905 and 0.917, for ADC were 0.831 and 0.829, a negative correlation was obtained from the ADC and ADC(slow) (all P<0.05). Conclusion: Mono-exponential and intravoxel incoherent motion (IVIM) model can be used to evaluate the pathological differentiated grade of HCC, ADC and ADC(slow) value entailed the highest diagnostic performance.

Association between metabolic syndrome and vascular endothelium dysfunction in children and adolescents.

We aimed at investigating the association between metabolic syndrome (MS) and vascular endothelial cell dysfunction (ECD) in children and adolescents. Sixty children (30 obese children and 30 children with MS) were included in this retrospective analysis. Thirty healthy subjects were randomly selected as the control group. A series of indices/biomarkers known to be related to MS/ECD were determined using ELISA. Correlations between the variables measured were analyzed. Compared with the control group, PAI-1, vWF, VE-cad, TM, and VEGF were significantly increased in the MS group (P < 0.05). Adolescents in the obese group had significantly increased levels of serum PAI-1, VE-cad, TM, and VEGF as compared with the control group (P < 0.05). Further, vWF in the obese and control groups did not differ significantly (P = 0.556). Our results suggest that ECD is correlated with MS in children and adolescents. Pathophysiological changes of the vascular endothelium may exist in obese children who have yet to develope MS. PAI-1, vWF, VE-cad, TM, and VEGF could be used as biomarkers for predicting ECD. ECD that develops in patients with MS may be associated with obesity, elevated blood lipid, elevated blood glucose, and higher blood pressure.

Theory and laboratory study of a tall passive chamber for measuring gas fluxes at soil surface.

A tall passive flux chamber with a height significantly greater than its horizontal dimensions is proposed for measuring fluxes of volatile organic compounds (VOCs) at the soil surface. The main feature of this tall chamber is the presence of a vertical concentration gradient of the target gas in the chamber. The emission and transport behavior of the target gas in the soil-chamber system are analyzed using the diffusion theory. A mathematical model is developed to estimate the flux from the soil into the tall chamber, providing the target gas establishes a detectable vertical concentration gradient in the chamber. To obtain the data required for calculating flux, only two gas concentrations (C1 and C2) at two heights (h1 and h2) within the chamber need to be measured at the end of a short chamber placement time (tp). To evaluate the applicability of the tall chamber for measuring flux, several laboratory tests have been conducted, using CH2Cl2 and CH3Br as the target gases. The results indicate that the proposed tall chamber has promising potential as a method for measuring fluxes of VOCs at the soil surface.