Facile synthesis of arabinoadenosine 3'-phosphate.
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Adenosine Monophosphate↗
Biomedical subjects
R Mengel
Publications and source records attributed to R Mengel.
Nucleic acid related compounds.22. Transformation of ribonucleoside 2,3'-O-ortho esters into halo, deoxy, and epoxy sugar nucleosides using acyl halides. Mechanism and structure of products.
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Acylation↗
Nucleic acid related compounds. 23. Transformation of ribonucleoside 2',3'-O-ortho esters into unsaturated and deoxy sugar nucleosides via enol ester-substituted iodo intermediates.
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Chemical Phenomena↗
Nucleic acid related compounds. 11. Adenosine 2',3'-ribo-epoxide. Synthesis, intramolecular degradation, and transformation into 3'-substituted xylofuranosyl nucleosides and the lyxo-epoxide.
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Adenine↗
Characterization of an endogenous transcription inhibitor from Physarum polycephalum.
A substance has been purified from isolated nuclei of Physarum polycephalum by equilibrium and velocity gradient centrifugations, ion exchange chromatography and gel filtration which has a high molecular weight, can be labeled in vivo with 32P, is heat stable and resistant to amylases, proteases, nucleases and phosphodiesterase but is sensitive to phosphatases or hydrolysis. This material consists of phosphate and glycerol. It selectively inhibits in vitro transcription of RNA polymerases, predominantly the homologous enzyme A by binding to the enzyme. In the presence of this inhibitor of transcription a stable RNA polymerase-template complex cannot be formed. Binding to and inactivation of RNA polymerase is reversible at high ionic strength.
Cell Nucleus↗
An in vitro study of the treatment of implant surfaces with different instruments.
The aim of this in vitro study using implants and abutments was to examine traces left by various cleaning instruments and to determine the quantity of substance removal. The implants and relevant abutments were Screw-Vent implants (Dentsply), titanium plasma-coated full-screw implants (Straumann), and standard Brånemark implants (Nobel Biocare). The instruments used were titanium curettes, Gracey curettes, plastic curettes, rubber cups with Zircate prophy paste, the Cavitron Jet ultrasonic scaler with universal inserts and airpolishing nozzles with Prophy-Jet cleaning powder, and the Densonic sonic scaler with SofTip disposable prophy tips and universal tips. Two test fields (2 x 2 mm) on the respective implant head and abutment underwent standard treatment with each instrument. With the full-screw implants, an additional two test fields were examined from the transition of the titanium plasma coating to the implant head. Untreated implants and abutment surfaces served as controls. The treated and untreated surfaces were examined by scanning electron microscopy for work traces and by optical laser profilometry for substance removal. The results showed that the Cavitron Jet ultrasonic unit, the Densonic sonic scaler with universal tips, and the Gracey curette left pronounced traces and induced high substance removal. The titanium curette and the Densonic sonic scaler with SofTip disposable prophy tips left virtually no traces and removed very little substance. The rubber cup, the plastic curette, and the Cavitron Jet airpolishing system left the implant surfaces unchanged. All instruments apart from the rubber cup and Cavitron Jet airpolishing system left pronounced traces at the transition of the implant head to the titanium plasma coating of the full-screw implants. The Cavitron Jet airpolishing system, the rubber cup, the plastic curette, and, with some reservations, the Densonic sonic scaler with SofTip plastic fittings and the titanium curette, appear to be suitable for cleaning implant surfaces.
Air Pressure↗