Spin-Trapping von Radikalen bei der Zersetzung aromatischer Diazoniumsalze mittels Ultraschall

Spin Trapping of Radicals Formed during the Decomposition of Aromatic Diazonium Salts by Ultrasound The decomposition of aromatic diazonium compounds ArN₂^⊕X^⊖ (Ar = phenyl, 2,5-diethoxy-4-(N-morpholino)phenyl; X = BF₄, PF₆, B(C₆H₅)₄, SCN, OCN,N₃; 1a , 1c–f , 2b–f ) by ultrasonic waves has been studied by e.s.r. The spin trapping technique has been shown to be a suitable method for the detection of free radical intermediates.     

Polyvalent choline phosphate as a universal biomembrane adhesive

Phospholipids in the cell membranes of all eukaryotic cells contain phosphatidyl choline (PC) as the headgroup. Here we show that hyperbranched polyglycerols (HPGs) decorated with the 'PC-inverse' choline phosphate (CP) in a polyvalent fashion can electrostatically bind to a variety of cell membranes and to PC-containing liposomes, the binding strength depending on the number density of CP groups per macromolecule. We also show that HPG-CPs can cause cells to adhere with varying affinity to other cells, and that binding can be reversed by subsequent exposure to low molecular weight HPGs carrying small numbers of PCs. Moreover, PC-rich membranes adsorb and rapidly internalize fluorescent HPG-CP but not HPG-PC molecules, which suggests that HPG-CPs could be used as drug-delivery agents. CP-decorated polymers should find broad use, for instance as tissue sealants and in the self-assembly of lipid nanostructures.     

Shelf-Life of Pasteurized Fluid Milk as Affected by Age of Raw Milk

Increasing raw milk storage time prior to pasteurization may affect product shelf-life. Raw milk was stored at 4.5°C for 0, 2, 4, and 6 days prior to pasteurizing. Milk samples from each pasteurized lot were analyzed after continuous storage at 4.5°C for 0, 4, 8, 12, 16, and 20 days. Both raw and pasteurized samples were analyzed for coliforms, psychrotrophs, and total bacteria counts. Flavor scores were also determined. No correlations were significant between raw or pasteurized samples and total bacteria or coliform counts. Related were flavor score and days held raw, shelf-life of the resulting pasteurized product, and interaction of days held raw and shelf-life of the pasteurized product. Psychrotrophic counts and age of the raw milk were correlated. From correlations of flavor scores with shelf-life of the milk, a predictive equation was: Flavor score = 8.00 – .88 R – .11 P – .0015 P² – .009 R P, where R is days held raw and P is shelf-life of the pasteurized product.     

Intraneural synovial sarcoma

This report describes and discusses the clinical, MRI, and pathologic findings in a case of synovial sarcoma arising within a peripheral nerve. Intraneural origin of synovial sarcoma is very unusual, and the MR imaging appearance of this condition has not been previously reported. MR imaging was valuable, as it showed the intraneural location and extent of the tumor, but it did not allow a specific histologic diagnosis.     

Sphenopalatine blocks in the treatment of pain in fibromyalgia and myofascial pain syndrome

Sphenopalatine blocks have been used to treat pain for more than 80 years. Anecdotal support for sphenopalatine ganglion blocks has been very strong in those who believe in the technique, but the research results have been inconclusive. Therefore, a double blind, placebo-controlled study was performed on 61 patients, 42 with fibromyalgia and 19 with myofascial pain syndrome. Pain was measured using visual analogue scales prior to treatment, during treatment, and 28 days after the treatment. Headaches were evaluated in frequency and location prior to and after treatment. Sphenopalatine ganglion blocks were performed under direct vision using 4% lidocaine and sterile water as a placebo. Analysis of the results showed no statistical differences between the lidocaine and the placebo groups.     

Model discrimination for the propionic acid diffusion into hydrogel beads using lifetime confocal laser scanning microscopy

Hydrogels are increasingly used for the entrapment of biocatalysts, especially for the use of enzymes in organic solvent systems. Hence, it is necessary to understand the influence of the hydrogel matrix on the transport kinetics (diffusion and phase transfer) and on the reaction kinetics (activity and stability of the enzymes). Here, the diffusion of propionic acid into Ca-alginate hydrogel beads is studied using a structured methodology, model-based experimental analysis (MEXA).The basis for all further investigations is a rigorous model of all processes occurring during the diffusion of the propionic acid into the Ca-alginate hydrogel bead. As competing model assumptions the Fickian and Nernst-Planck diffusion laws are integrated. Then, an optimal experimental design is performed to determine those experiments that allow an efficient discrimination of the rival model candidates. The change in pH-value over time resulting from the diffusion of propionic acid into the hydrogel bead is observed in the centre of the hydrogel bead. The fluorescent pH-indicator resorufin shows pH-dependent lifetimes that are measured by time-correlated single photon counting using a confocal laser scanning microscope at high temporal resolution (every 1 s). To our knowledge lifetime confocal laser scanning microscopy is used for the first time in this study for the quantification of dynamic pH-changes in macroscopically large particles. The model parameters for each candidate model are estimated based on 16 independent experimental data sets. Finally, the likelihood function is used to evaluate and discriminate the competing diffusion laws.For the diffusion of propionic acid into spherical Ca-alginate hydrogel beads, it could be shown that Fickian diffusion is not able to describe the process accurately in contrast to Nernst-Planck diffusion. The influence of the Ca-alginate hydrogel density was found to be insignificant for the estimated diffusion coefficient.