MRT of experimental liver abscesses: a comparison of a new blood pool contrast medium with gadolinium-DTPA in animal experiments

PURPOSE: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. METHODS: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 mumol/kg dose of gadolinium polymer and of 100 mumol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. RESULTS: The interindividual comparison (unpaired T-test, p < 0.05) yielded significant differences of the relative signal intensities of the abscess centre (at any time point after contrast-media application), abscess wall (between 15 and 60 minutes after contrast media application), and portal vein (between 30 seconds and 7.5 minutes after contrast media application). The interindividual comparison showed a significantly higher abscess centre-liver contrast (between 30 seconds and 12.5 minutes after contrast media application) and a significantly higher abscess wall-centre contrast (between two and 7.5 minutes after contrast media application) after the application of gadolinium polymer compared with gadopentetate dimeglumine. CONCLUSION: In this animal model, the higher abscess centre-liver contrast after the application of gadolinium polymer was the basis for a better and prolonged visibility of the abscesses, as compared with images acquired after injection of gadopentetate dimeglumine.     

Potential Antitumor Effects of 6-Gingerol in p53-Dependent Mitochondrial Apoptosis and Inhibition of Tumor Sphere Formation in Breast Cancer Cells

Hormone-specific anticancer drugs for breast cancer treatment can cause serious side effects. Thus, treatment with natural compounds has been considered a better approach as this minimizes side effects and has multiple targets. 6-Gingerol is an active polyphenol in ginger with various modalities, including anticancer activity, although its mechanism of action remains unknown. Increases in the level of reactive oxygen species (ROS) can lead to DNA damage and the induction of DNA damage response (DDR) mechanism, leading to cell cycle arrest apoptosis and tumorsphere suppression. Epidermal growth factor receptor (EGFR) promotes tumor growth by stimulating signaling of downstream targets that in turn activates tumor protein 53 (p53) to promote apoptosis. Here we assessed the effect of 6-gingerol treatment on MDA-MB-231 and MCF-7 breast cancer cell lines. 6-Gingerol induced cellular and mitochondrial ROS that elevated DDR through ataxia-telangiectasia mutated and p53 activation. 6-Gingerol also induced G0/G1 cell cycle arrest and mitochondrial apoptosis by mediating the BAX/BCL-2 ratio and release of cytochrome c. It also exhibited a suppression ability of tumorsphere formation in breast cancer cells. EGFR/Src/STAT3 signaling was also determined to be responsible for p53 activation and that 6-gingerol induced p53-dependent intrinsic apoptosis in breast cancer cells. Therefore, 6-gingerol may be used as a candidate drug against hormone-dependent breast cancer cells.     

Isobutylene polymerization in the presence of t-BuCl/SnCl4

Summary The effect of tert-butyl chloride in the polymerizations of isobutylene carried out in the presence of SnCl₄ in dichloromethane at temperatures-20°C and-78°C was investigated. Synthesized polyisobutylene samples showed a bimodal molecular weight distribution (MWD) and it was found that the weight content of the lowermolecular weight (LMW) fraction increased with increasing t-BuCl concentration in the polymerization mixture. The effect of ageing of the initiation mixture t-BuCl/SnCl₄ in CH₂Cl₂ prepared in advance on MWD of the PIB samples was also studied. Ageing of the initiation system supports the formation of the LMW fraction and this oily PIB is the only product of the polymerization at-20°C, .     

Solvent induced crystallization of syndiotactic poly(methyl methacrylate) relation to the formation of polymer aggregates in solution

Polymer Bulletin - Solutions of syndiotactic (s) poly (methyl methacrylate) (PMMA) and samples of solid s-PMMA prepared from these solutions were studied by NMR and infrared (IR) spectroscopy and...     

Exploring the costs of technical debt management – a case study

Technical debt is a metaphor for delayed software maintenance tasks. Incurring technical debt may bring short-term benefits to a project, but such benefits are often achieved at the cost of extra work in future, analogous to paying interest on the debt. Currently technical debt is managed implicitly, if at all. However, on large systems, it is too easy to lose track of delayed tasks or to misunderstand their impact. Therefore, we have proposed a new approach to managing technical debt, which we believe to be helpful for software managers to make informed decisions. In this study we explored the costs of the new approach by tracking the technical debt management activities in an on-going software project. The results from the study provided insights into the impact of technical debt management on software projects. In particular, we found that there is a significant start-up cost when beginning to track and monitor technical debt, but the cost of ongoing management soon declines to very reasonable levels.     

Mode-locked laser cavities with a single prism for dispersion compensation

We demonstrate the use of a single prism for adjustable dispersion compensation in a mode-locked laser cavity, instead of the standard approach with a prism pair. A simple model based on the prism-pair configuration is presented to determine the group-velocity dispersion by use of ray optics to trace the wavelength-dependent optical axes through the cavity. We experimentally demonstrated this concept with a passively mode-locked diode-pumped Nd:glass laser producing 200-fs pulses with a 200-mW average output power, using only one intracavity prism. The advantages of such a cavity design are simple alignment, reduced loss, and lossless wavelength tunability This technique can be generalized to other angularly dispersive elements such as prismatic output couplers.     

Detection of colorectal adenoma and cancer based on transthyretin and C3a-desArg serum levels

Colorectal cancer is the second leading cause of cancer death, and it develops from benign colorectal adenomas in over 95% of patients. Early detection of these cancer precursors by screening tests and their removal can potentially eradicate more than 95% of colorectal cancers before they develop. To discover sensitive and specific biomarkers for improvement of pre‐clinical diagnosis of colorectal adenoma and cancer, we analysed in two independent studies (n = 87 and n = 83 patients) serum samples from colorectal cancer (stage III), colorectal adenoma and control patients using SELDI‐TOF‐MS. Extensive statistical analysis was performed to establish homogeneous patient groups based on their clinical data. Two biomarkers that were each able to distinguish control patients from either colorectal adenoma or colorectal cancer patients (p<0.001) were identified as transthyretin (pre‐albumin) and C3a‐desArg by MS/MS and were further validated by antibody‐based assays (radial immunodiffusion, ELISA). A combination of both proteins clearly indicated the presence of colorectal adenoma or carcinoma. Using a cut‐off of <0.225 g/L for transthyretin and >1974 ng/mL for C3a‐desArg, we found a sensitivity and specificity for colorectal adenoma of 96% and 70%, respectively.     

Untersuchung der Stabilität der doppeltgespeisten Drehstrommaschine mit Hilfe eines linearisierten Modells

Übersicht Die dynamischen Gleichungen der doppeltgespeisten Asynchronmaschine werden um einen stationären Arbeitspunkt linearisiert. Die numerische Berechnung der Eigenwerte des Systems erlaubt eine Stabilitätsuntersuchung für beliebige Maschinenparameter und Arbeitspunkte. Eine digitale Simulation des elektromechanischen Systems bestätigt die durch die Eigenwertberechnung erhaltenen Ergebnisse.

---

Stability analysis of the doubly fed asynchronous machine using a linearized modell

Contents The dynamical equations of the doubly fed asynchronous machine are linearized about a steady state operating point. The numerical calculation of the eigenvalues of the system makes a stability analysis possible for every set of machine constants and for every operating point. A digital simulation of the electromechanical system corroborates the results obtained via eigenvalue calculation.