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The chirality of biopolymers remains one of the mysteries of Life. For such objects, the phenomenon of supramolecular chirality (SMC) is vital. Enantiomers can be recognized by the adsorption on surfaces with SMC. However, the mechanisms of such chiral recognition are still unknown. In this work, the adsorption kinetics of menthol test enantiomers on the surfaces of γ-glycine and NiSO4•6H2O chiral crystals was studied. It was found that the difference in adsorption was observed in nonequilibrium state more often than in equilibrium. If the enantioselectivity in equilibrium state was observed, the enantioselectivity coefficient α at nonequilibrium conditions was higher. The maximum α in nonequilibrium state was 2.44 for γ-glycine crystals and 2.12 for NiSO4•6H2O crystals. Even if no differences in adsorption were observed under adsorption-desorption equilibrium conditions, a significant enantioselectivity at nonequilibrium conditions was found. This has proved the possibility of chiral recognition on surfaces with SMC by the differences in adsorption rates. Such novel chiral recognition mechanism can provide enhanced enantioselectivity in adsorption, catalysis, chromatographic separation, and chemical sensing.

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In using a flow-injection recirculating-catalysis system developed by us to research the simultaneous quantification for peroxidase and ascorbate, it was discovered that the concentrations of peroxidase activity and ascorbate are correlative with the slope and the negative intercept of the linear response curve during a peroxidase-catalyzed kinetic course. Therefore, based on this finding, a new analytical method and a simplified equation for quantifying the peroxidase activity concentration were proposed, Then, test conditions were optimized, finally the use of the method has realized the simultaneous determination for peroxidase of 2-40 U/L and ascorbate of 0.4-12 mg/L in various vegetables (60 µL). The assayed results were consistent with the comparison method, in which the repeatability (RSD < 1.43%, n = 11) was satisfactory. Another important conclusion obtained in this study is that the determination of the peroxidase activity in biosamples must use the kinetic curve method for fear of the influence from the ascorbate's lag phase.

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Background Dynamic contrast-enhanced (DCE) MRI sequences plays a vital role in diagnosing breast masses with high sensitivity and specificity as compared to other diagnostic modalities. The addition of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values significantly improves diagnostic accuracy. This study aimed to study the breast masses on DCE-MRI, restricted diffusion on DWI, ADC values, and choline peak on spectroscopy in breast cancer diagnosis. Material and methods This study was a prospective observational study which involved subjects with breast lumps. Baseline data was collected from the patients along with pertinent clinical history and relevant laboratory investigations. MR mammography (MRM) was performed on a 1.5 Tesla MR Scanner (MAGNETOM® Avanto, Siemens AG, Munich Germany) using a dedicated double breast coil. Results Forty-one subjects were included with a total of 54 breast masses in them. The mean age of the study population was 47.1±14.7 years. From the MRI final diagnosis, the majority (53.70%) were diagnosed as malignant lesions and 46.30% as benign. Out of 20 lesions diagnosed as benign on histopathology, only five percent had ADC value <1.3 ×10-3mm2/s, and the majority (95%) had ADC value >1.3 ×10-3mm2/s. All 20 lesions were circumscribed, ovoid, or round in shape showing no restricted diffusion on DWI, with corresponding ADC value of >1.3×10-3mm2/s, homogeneous post-contrast enhancement, or with dark internal septations, type I kinetic enhancement curve, and they showed no choline peak on spectroscopy. Out of 34 malignant lesions diagnosed on histopathology, the majority (85.29%) displayed restricted diffusion on DWI and had an ADC value of <1.3×10-3mm2/s, most of them had spiculated margins, type II/ III kinetic curve with choline peak on spectroscopy. Conclusion Multiparametric MR mammography, which included DCE-MRM, DWI, ADC values, and spectroscopy, correlated well with the histopathological diagnosis of benign and malignant breast masses.

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Accurate collection of extracted material represents a technical problem in supercritical fluid extraction because trapping should be performed in severe conditions of rapidly moving and freezing expanded fluid. We have developed a simple device for effective sample collection in analytical-scale supercritical fluid extraction. The device consists of a cyclone separator equipped with a spray trap and a heated check valve. The cyclone separator and spray trap are manufactured from a light polymer via 3D printing and are quick-detachable, which encourages its use in applications where mass yield measurements are required. The device was compared to a standard tubing-and-vial approach in the task of building kinetic curves for the extraction from two aroma plants, namely, laurel and rosemary. The new device showed almost two-fold increase in extraction trapping, most probably due to better collection of volatile compounds. A curious effect of the number of mass measurement points per curve on apparent yield was observed. An increase in the number of points led to an increase in yield, probably due to the effect of the static-dynamic extract regime posed by the manner in which the device is used.

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European legislation has established a specific migration limit (SML) of 15 mg kg-1 for formaldehyde and 2.5 mg kg-1 for melamine. Formaldehyde resins are used in the manufacture of melamine kitchenware. Formaldehyde is listed in group 1 of the IARC list of carcinogenic compounds. To determine the quantity of formaldehyde and melamine as potential migrants from different types of melamine kitchenware (glass, mug, cutlery, big cup and bowl), a HPLC-DAD method has been implemented. This method is an alternative to the ones proposed in technical guidelines to determine formaldehyde by UV-vis spectrophotometry and melamine by HPLC. The final objective was to fit the migration kinetic curves of these two analytes in melamine kitchenware. After the method was validated, decision limit (CCα) and detection capability (CCß) were calculated for both analytes, when the probabilities of false positive (α) and false negative (ß) were fixed at 0.05; being CCß 0.269 mg L-1 and 0.311 mg L-1 for melamine and formaldehyde respectively. CCα and CCß were also calculated at the SML of both analytes. The migration testing were conducted with simulant B (3% acetic acid (w/v) in aqueous solution), the conditions of each exposure being 70 °C for 2 h. The quantities of melamine and formaldehyde found in the third exposure of the total kitchenware analysed were between 0.21 and 1.09 mg L-1 and between 0.55 and 3.86 mg L-1, respectively. Migration kinetic curves were built for each type of kitchenware with the data of sixteen consecutive migration cycles (70 °C each 30 min). The SML for melamine was surpassed in the mug, in the big cup and in the bowl after eleven, thirteen and one cycles, respectively. When more cycles were carried out in the mug, the values of the accumulated quantity of formaldehyde and melamine were 15.30 and 6.79 mg L-1, respectively, after thirty-two cycles. Both concentrations exceeded the corresponding SML.

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The shape of the kinetic curve for gadobutrol is reportedly different compared with that for other conventional contrast agents. We speculate that the shape of gadobutrol kinetic curve may be influenced by different magnetic resonance imaging (MRI) protocols and evaluation methods. The purpose of our study was to assess the influence between gadobutrol and other conventional contrast agent (gadodiamide hydrate) on the kinetic curve in invasive ductal carcinoma (IDC). We assessed 139 women of IDC in this study. Gadodiamide hydrate (2 ml/s) was administered to 69 women, and gadobutrol (1 ml/s) was administrated to 70 women, both contrast agents at 0.1 mmol/kg BW. When the kinetic curves of contrast agents were evaluated between by Breast Imaging Reporting and Data System (BI-RADS) 4th edition and BI-RADS 5th edition, suggested that the analysis method of BI-RADS may affect. Patient group who were administered gadobutrol demonstrated a lower washout rate when compared with patient group who were administered gadodiamide hydrate administration (P<0.01). These results suggest that the kinetic curve characteristics of gadobutrol are an important consideration in diagnosis. Therefore, it is necessary to perform image diagnosis by considering the influence of the contrast agent and the analysis method, when image diagnostic doctor perform image diagnosis.

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BACKGROUND AND OBJECTIVE: Liver cancer is the tenth most common cancer in the USA, and its incidence has been increasing for several decades. Early detection, diagnosis, and treatment of the disease are very important. Computed tomography (CT) is one of the most common and robust imaging techniques for the detection of liver cancer. CT scanners can provide multiple-phase sequential scans of the whole liver. In this study, we proposed a computer-aided diagnosis (CAD) system to diagnose liver cancer using the features of tumors obtained from multiphase CT images. METHODS: A total of 71 histologically-proven liver tumors including 49 benign and 22 malignant lesions were evaluated with the proposed CAD system to evaluate its performance. Tumors were identified by the user and then segmented using a region growing algorithm. After tumor segmentation, three kinds of features were obtained for each tumor, including texture, shape, and kinetic curve. The texture was quantified using 3 dimensional (3-D) texture data of the tumor based on the grey level co-occurrence matrix (GLCM). Compactness, margin, and an elliptic model were used to describe the 3-D shape of the tumor. The kinetic curve was established from each phase of tumor and represented as variations in density between each phase. Backward elimination was used to select the best combination of features, and binary logistic regression analysis was used to classify the tumors with leave-one-out cross validation. RESULTS: The accuracy and sensitivity for the texture were 71.82% and 68.18%, respectively, which were better than for the shape and kinetic curve under closed specificity. Combining all of the features achieved the highest accuracy (58/71, 81.69%), sensitivity (18/22, 81.82%), and specificity (40/49, 81.63%). The Az value of combining all features was 0.8713. CONCLUSIONS: Combining texture, shape, and kinetic curve features may be able to differentiate benign from malignant tumors in the liver using our proposed CAD system.

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OBJECTIVE: Our purpose was to evaluate imaging findings of breast cancers according to the dominant stroma type by using kinetic curve analysis and model-based perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging. METHODS: From March 2011 to September 2011, 64 cancers in 64 patients were included for data analysis. Kinetic curve analysis and model based perfusion parameters (Ktrans, Kep and Ve) were obtained using dynamic contrast-enhanced magnetic resonance imaging and post-processing software. Imaging characteristics were analyzed according to the tumor-stroma ratio and dominant stroma type. RESULTS: Ve values were significantly lower in tumors with more than 50% cellularity (0.44 vs. 0.29, p=0.008). Histologic grade, estrogen receptor status and subtype of cancer (triple negative versus non-triple negative) were significantly different (p=0.009, p=0.019 and p=0.03, respectively). Median Kep values were different between collagen dominant, fibroblast dominant and lymphocyte dominant groups. By post hoc comparisons, mean Kep values were significantly higher in lymphocyte dominant group than collagen dominant group (p=0.003). Ktrans and Ve values were not significantly different according to dominant stroma type (p=0.351 and p=0.257, respectively). In multivariate regression analysis, nuclear grade (p=0.021) and dominant stroma type (collagen dominant, p=0.017) were independently correlated with Kep values. In terms of the dominant stroma type, the collagen dominant type showed a decrease of 0.247 in Kep values, compared with the fibroblast-dominant type (p=0.017). CONCLUSIONS: Ve values were significantly lower in tumors with high tumor-stroma ratio. Kep values were significantly lower in breast cancers with dominant collagen type and higher in cancers with high nuclear grade.

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