Search

The void coalescence and interaction in dynamic tensile fracture of ductile metals were investigated by using axial symmetric finite element analysis. The influences of initial ligament distance between voids and loading strain rate on the void coalescence process were discussed. The start time of void coalescence was estimated quantitatively through correlated shape evolution of the voids. The measurement results show that the critical ligament distance at the start time of coalescence is approximately a half of void diameter, which is independent of initial separation distance between voids and strain rate. In reality, the voids may interact through their plastic fields. However, a critical plastic strain threshold in the ligament zones is needed to drive the void coalescence. Assuming that the voids are uniformly distributed within the damaged material, the critical ligament distance are consistent to the critical porosity in physical essence, and can be transformed each other. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To identify characteristic computed tomographic (CT) and computer-derived features of hamartomas manifesting as small pulmonary nodules. Methods: Individuals with a diagnosis of hamartoma were identified among participants in the International Early Lung Cancer Action Program and were included if there thin section CT images that included the entire nodule. The CT findings were reviewed to determine the nodule consistency (solid, part-solid, nonsolid), nodule diameter (average of length and width), shape (round, lobulated, neither) and edge (smooth, not smooth). Computer measures of nodule compactness, sphericity, surface regularity and gradient (change in gray-scale between the nodule and the surrounding parenchyma) were determined. Volume doubling time (VDT) was also determined for those with at least two scans with similar imaging acquisitions. Results: A total of 21 cases of hamartomas that had histologic or cytologic confirmation were identified. The median age was 60 and 12 (57%) were men. Average diameter was 10.7 mm (5–20.7 mm). All were solid in consistency and were described by the radiologist as having either round or lobulated shape with a smooth edge. None had pathognomonic radiologic findings for hamartoma. Computer measures demonstrated that all were compact and spherical, with a regular surface and a sharp margin between the nodule and surrounding parenchyma. Of nine on whom the VDT could be calculated, eight had VDTs longer than 450 days. Conclusion: Both radiologist and computer derived features of small hamartomas suggest a consistent presentation for these lesions which may be helpful in distinguishing them from other types of nodules. [Copyright &y& Elsevier]

Abstract: Purpose: To retrospectively evaluate whether baseline nodule density or changes in density or nodule features could be used to discriminate between benign and malignant solid indeterminate nodules. Materials and methods: Solid indeterminate nodules between 50 and 500mm3 (4.6–9.8mm) were assessed at 3 and 12 months after baseline lung cancer screening (NELSON study). Nodules were classified based on morphology (spherical or non-spherical), shape (round, polygonal or irregular) and margin (smooth, lobulated, spiculated or irregular). The mean CT density of the nodule was automatically generated in Hounsfield units (HU) by the Lungcare© software. Results: From April 2004 to July 2006, 7310 participants underwent baseline screening. In 312 participants 372 solid purely intra-parenchymal nodules were found. Of them, 16 (4%) were malignant. Benign nodules were 82.8mm3 (5.4mm) and malignant nodules 274.5mm3 (8.1mm) (p =0.000). Baseline CT density for benign nodules was 42.7HU and for malignant nodules −2.2HU (p =ns). The median change in density for benign nodules was −0.1HU and for malignant nodules 12.8HU (p <0.05). Compared to benign nodules, malignant nodules were more often non-spherical, irregular, lobulated or spiculated at baseline, 3-month and 1-year follow-up (p <0.0001). In the majority of the benign and malignant nodules there was no change in morphology, shape and margin during 1 year of follow-up (p =ns). Conclusion: Baseline nodule density and changes in nodule features cannot be used to discriminate between benign and malignant solid indeterminate pulmonary nodules, but an increase in density is suggestive for malignancy and requires a shorter follow-up or a biopsy. [Copyright &y& Elsevier]

Abstract: Purpose: To evaluate prospectively the value of size, shape, margin and density in discriminating between benign and malignant CT screen detected solid non-calcified pulmonary nodules. Material and methods: This study was institutional review board approved. For this study 405 participants of the NELSON lung cancer screening trial with 469 indeterminate or potentially malignant solid pulmonary nodules (>50mm3) were selected. The nodules were classified based on size, shape (round, polygonal, irregular) and margin (smooth, lobulated, spiculated). Mean nodule density and nodule volume were automatically generated by software. Analyses were performed by univariate and multivariate logistic regression. Results were presented as likelihood ratios (LR) with 95% confidence intervals (CI). Receiver operating characteristic analysis was performed for mean density as predictor for lung cancer. Results: Of the 469 nodules, 387 (83%) were between 50 and 500mm3, 82 (17%) >500mm3, 59 (13%) malignant, 410 (87%) benign. The median size of the nodules was 103mm3 (range 50–5486mm3). In multivariate analysis lobulated nodules had LR of 11 compared to smooth; spiculated nodules a LR of 7 compared to smooth; irregular nodules a LR of 6 compared to round and polygonal; volume a LR of 3. The mean nodule CT density did not predict the presence of lung cancer (AUC 0.37, 95% CI 0.32–0.43). Conclusion: In solid non-calcified nodules larger than 50mm3, size and to a lesser extent a lobulated or spiculated margin and irregular shape increased the likelihood that a nodule was malignant. Nodule density had no discriminative power. [Copyright &y& Elsevier]

Summary: In December 2003, the Dutch–Belgian NELSON trial, a Dutch acronym for “Nederlands-Leuvens Longkanker Screenings ONderzoek”, has been launched. Primary objective of the NELSON trial is to investigate whether screening for lung cancer by 16-detector multi-slice CT with 16mm×0.75mm collimation and 15mm table feed per rotation (pitch=1.5) in year 1, 2 and 4 will lead to a decrease in lung cancer mortality in high risk subjects of at least 25% compared to a control group which receives no screening. In this paper, the screening regimen and the classification and management of the screen-detected nodules at baseline and incidence screening is presented. This is the first large lung cancer screening trial in which the nodule management protocol is based on volumetric nodule assessment and the presence or absence of growth. Furthermore, the quality assurance measures and the NELSON management system (NMS) are presented. [Copyright &y& Elsevier]

The cooling capacity of a typical dilution refrigerator is mainly determined by the circulating flow of the He-3 in the system, which is usually realized by the external circulation pump. In order to increase the concentration of circulating He-3, the still often take the orifice structure to limit the influence of the superfluid helium film, and this structure will also have a certain impact on the flow rate of He-3. This paper summarizes the flow rate models of each part of the orifice structure, and establishes a model related to the influence of pumping speed and the diameter of orifice on the flow rate of circulating He-3. The relationship between pumping speed and flow rate is developed and the relation is divided into three phases for detailed analysis. It is found that the flow rate and the concentration of circulating He-3 increase first and then decrease with the increasing diameter of orifice at a certain pumping speed, and the possible reasons for this phenomenon are analyzed. The results indicate that there is an optimal orifice diameter at a determined pumping speed. [ABSTRACT FROM AUTHOR]

Summary: The high frequency of non-calcified pulmonary nodules (NCN) <10mm incidentally detected on a multi-detector CT (MDCT) of the chest raises the question of how clinicians and radiologists should deal with these nodules. Management algorithms for solitary pulmonary nodules >10mm do not carry across to sub-centimeter lesions. Purpose of this review is to provide a 10-step approach for routinely detected sub-centimeter NCN on a MDCT in healthy persons in order to be able to make an optimal discrimination between benign and malignant NCNs. Recommendations are primarily based on individual cancer risk, the presence or absence of calcifications and nodule size. In nodules >4–5mm nodule consistency, margin and shape should be taken into account. Next steps in the nodule evaluation are the assessment of localization, nodule number, presence or absence of growth and volume doubling time. Growth is defined as a volume doubling time of 400 days or less, based on volumetry. For nodules <4mm, a follow-up CT at 12 months is recommended in high risk persons, whilst for low-risk persons no follow-up is needed. If no growth is observed at 12 months, no further follow-up is required. For solid, smooth or attached indeterminate NCN between 5 and 10mm we recommend an annual repeat scan, whilst for purely intra-parenchymal nodules a 3-month repeat scan should be made to assess growth. Growing lesions with a volume doubling time <400 days require further work-up and diagnosis, otherwise an annual repeat scan to assess growth is recommended. [Copyright &y& Elsevier]

Two new and six known steroidal glucosides were isolated from the tuber ofOphiopogon japonicus. The new steroidal glucosides were established as (20R,25R)-26-O-β-d-glucopyranosyl-3β,26-dihydroxycholest-5-en-16,22-dioxo-3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside (1) and 26-O-β-d-glucopyranosyl-(25R)-furost-5-en-3β,14α,17α,22α,26-pentaol-3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranoside (3) on the basis of spectroscopic data as well as chemical evidence. [ABSTRACT FROM PUBLISHER]

A new dammarane triterpenoid glycoside named cyclocarioside J (1) and other three known triterpenoid glycosides were isolated from the leaves of Cyclocarya paliurus. Based on ESI-MS, HR-ESI-MS, 1H NMR, 13C NMR, and 2D NMR techniques including 1H–1H COSY, HMBC, HMQC, and NOESY correlations, the structure of cyclocarioside J was elucidated as (20S,24R)-epoxydammarane 3β,12β,25-trihydroxy-12-O-β-d-quinovopyranosyl-3-O-α-l-arabinopyranoside. [ABSTRACT FROM AUTHOR]

Besides four known compounds, a new triterpenoid saponin was isolated from the stems of Gymnema sylvestre. The structure of the new triterpenoid saponin was established as 3β,16β,22α-trihydroxy-olean-12-ene 3-O-β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside (1) on the basis of 1D and 2D NMR techniques, including COSY, HMBC, HMQC, and NOESY correlations. Four known compounds 2, 3, 4, and 5 were identified on the basis of spectroscopic data. [ABSTRACT FROM PUBLISHER]

Two new furostanol saponins were isolated from the fruits of Tribulus terrestris L. Their structures were established as 26-O-β-d-glucopyranosyl-(25S)-5α-furost-20(22)-en-3β,26-diol-3-O-α-l-rhamnopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 4)]-β-d-galactopyranoside (1) and 26-O-β-d-glucopyranosyl-(25S)-5α-furost-20(22)-en-12-one-3β,26-diol-3-O-β-d-galactopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (2) on the basis of spectroscopic data as well as chemical evidence. [ABSTRACT FROM AUTHOR]

Two new furostanol saponins, tribufurosides D (1) and E (2), were isolated from the fruits of Tribulus terrestris L. With the help of chemical and spectral analyses (IR, MS, 1D, and 2D NMR), the structures of the two new furostanol saponins were established as 26-O-β-d-glucopyranosyl-(25S)-5α-furost-12-one-2α,3β,22α,26-tetraol-3-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (1) and 26-O-β-d-glucopyranosyl-(25R)-5α-furost-12-one-2α,3β,22α,26-tetraol-3-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (2). [ABSTRACT FROM AUTHOR]

Purpose: To evaluate prospectively the value of size, shape, margin and density in discriminating between benign and malignant CT screen detected solid non-calcified pulmonary nodules. Material and Methods: This study was institutional review board approved. For this study 405 participants of the NELSON lung cancer screening trial with 469 indeterminate or potentially malignant solid pulmonary nodules (>50mm3) were selected. The nodules were classified based on size, shape (round, polygonal, irregular) and margin (smooth, lobulated, spiculated). Mean nodule density and nodule volume were automatically generated by software. Analyses were performed by univariate and multivariate logistic regression. Results were presented as likelihood ratios (LR) with 95% confidence intervals (CI). Receiver operating characteristic analysis was performed for mean density as predictor for lung cancer. Results: Of the 469 nodules, 387 (83%) were between 50 and 500mm3, 82 (17%) >500mm3, 59 (13%) malignant, 410 (87%) benign. The median size of the nodules was 103mm3 (range 50-5486mm3). In multivariate analysis lobulated nodules had LR of 11 compared to smooth; spiculated nodules a LR of 7 compared to smooth; irregular nodules a LR of 6 compared to round and polygonal; volume a LR of 3. The mean nodule CT density did not predict the presence of lung cancer (AUC 0.37, 95% CI 0.32-0.43). Conclusion: In solid non-calcified nodules larger than 50mm3, size and to a lesser extent a lobulated or spiculated margin and irregular shape increased the likelihood that a nodule was malignant. Nodule density had no discriminative power. [ABSTRACT FROM AUTHOR]

A new triterpenoid, saponin hehuanoside A, was isolated together with the known triterpenoid saponins 2, 3, and 4 from the stem bark of Albizia julibrissin. With the help of chemical and spectral analyzes (IR, MS, 1D-NMR, and 2D-NMR), the structure of the new triterpenoid saponin was elucidated as 21-O-[(6S)-2-trans-2,6-dimethyl-6-O-β-d-quinovopyranosyl-2,7-octadienoyl]-3-O-β-d-xylopyranosyl-(1 → 2)-β-d-fucopyranosyl-(1 → 6)-β-d-2-deoxy-2-acetamidoglucopyrasyl acacic acid 28-O-α-l-arabinofuranosyl-(1 → 4)-[-β-d-glucopyranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl ester (1). Three known triterpenoid saponins 2-4 were identified on the basis of spectroscopic data. [ABSTRACT FROM AUTHOR]

A new triterpenoid saponin, tenuifoside A, was isolated together with three known triterpenoid saponins 2, 3, and 4 from the roots of Polygala tenuifolia Willd. With the help of chemical and spectral analyses (IR, MS, 1D-NMR, and 2D-NMR), the structure of the new saponin was elucidated as 3-O-β-d-glucopyranosyl presenegenin 28-O-β-d-xylopyranosyl-(1 → 3)-β-d-xylopyranosyl-(1 → 4)-[β-d-apiofuranosyl-(1 → 3)]-α-l-rhamnopyranosyl-(1 → 2)-[4-O-p-methoxycinnamoyl]-[α-l-rhamnopyranosyl-(1 → 3)]-β-d-fucopyranosyl ester (1). Three known triterpenoid saponins (2-4) were identified on the basis of spectroscopic data. [ABSTRACT FROM AUTHOR]

A new furospirostanol saponin, ophiofurospiside A (1), was isolated together with the known steroidal glycosides 2, 3, and 4 from the tubers of Ophiopogon japonicus (Thunb.) Ker-Gawl. Using chemical and spectral analyses (IR, MS, 1D NMR, and 2D NMR), the structure of 1 was established as 26-O-β-d-glucopyranosyl-(22S, 25R)-furospirost-5-ene-3β, 17α, 26-triol-3-O-[α-l-rhamnopyranosyl-(1 → 2)]-[β-d-xylopyranosyl-(1 → 4)]-glucopyranoside (1). Three known steroidal saponins 2-4 were identified on the basis of spectroscopic data. [ABSTRACT FROM AUTHOR]

Two new furostanol saponins, tribufurosides B (1) and C (2), were isolated from the fruits of Tribulus terrestris L. With the help of chemical and spectral analyses (IR, MS, 1D NMR and 2D NMR), the structures of two new furostanol saponins were established as 26-O-β-d-glucopyranosyl-(25S)-5α-furost-20(22)-en-2α,3β,26-triol-3-O-β-d-galactopyranosyl(1 → 2)-β-d-glucopyranosyl(1 → 2)-β-d-galactopyranoside (1) and (25S)-5α-furost-20(22)-en-12-one-3β, 26-diol-26-O-β-d-glucopyranoside (2). [ABSTRACT FROM AUTHOR]

Two new triterpenoid saponins, named cernuaside C and D, have been isolated from Pulsatilla cernua (Thunb.) Bercht. et Opiz. The structures of the two new triterpenoid saponins were elucidated as 3-O-β-D-xylopyranosyl(1 → 2)-[α-L-rhamnopyranosyl(1 → 3)]-α-L-arabinopyranosyl oleanolic acid 28-α-L-rhamnopyranosyl(1 → 4)-β-D-glucopyranosyl(1 → 6)-β-D-glucopyranoside. (1) and 3-O-α-L-arabinopyranosyl (1 → 3)-α-L-rhamnopyranosyl(1 → 2)-α-L-arabinopyranosyl oleanolic acid 28-O-β-D-glucopyranoside (2) by 1D, 2D-NMR techniques, ESI-MS analysis as well as chemical methods. [ABSTRACT FROM AUTHOR]