Functionalization of Polyurethane/Urea Copolymers with Amide Groups by Polymer Treatment with Ammonia Plasma

Samples of porous foam from polyurethane/urea copolymers based on polyethylene glycol (PURPEG) were prepared in the form of 1-mm-thick discs of diameter 10 cm and exposed to ammonia plasma created by inductively coupled radiofrequency discharge in either low density (E mode) or high density (H mode). The evolution of surface composition and structure upon plasma treatment was characterized by X-ray photoelectron spectroscopy. Treatment in the H mode caused depletion of oxygen even after 2 s of treatment, whereas treatment in the E mode caused gentle functionalization with amide groups. The concentration of functional groups depended on the discharge power, and the best results were obtained at moderately high power just before the transition from E to H modes.     

1H‐, 13C‐, and 15N‐NMR chemical shifts for selected glucosides and ribosides of aromatic cytokinins

The ¹H and ¹³C NMR resonances of 16 purine glucosides were assigned by a combination of one‐ and two‐dimensional NMR experiments, including gs‐COSY, gs‐HSQC, and gs‐HMBC, in order to characterize the effect of substituent and the position of glucose unit on the NMR chemical shifts. In addition, ¹⁵N NMR chemical shifts for selected derivatives were investigated by using ¹H? ¹⁵N chemical shift correlation techniques. To map the influence of sugar moiety on the directly bonded nitrogen atom, selected N⁹‐glucosides and their ribose analogs were compared. Characteristic long‐range ¹H? ¹⁵N coupling constants, measured by using ¹H? ¹⁵N gradient‐selected single‐quantum multiple bond correlation (GSQMBC), are also reported and discussed. All compounds investigated here belong to cytokinins, an important group of plant hormones. Copyright © 2010 John Wiley & Sons, Ltd.     

Non-destructive method for the analysis of gold(I) cyanide plating baths Complexometric determination of nickel and indium

A method is described for rapid determination of nickel and indium in gold(I) cyanide baths containing large amounts of citric acid and/or sodium citrate, without previous destruction of organic matter. Gold is removed by extraction with ethyl acetate. In one aliquot of the solution indium is masked with thioglycollic acid and nickel is precipitated with sodium diethyldithiocarbamate, extracted into chloroform, stripped into water and determined complexometrically. In a second aliquot indium and nickel are precipitated together with the same reagent and stripped into water, then nickel is masked with 1,10-phenanthroline, and indium is determined by direct titration with EDTA.     

The putative lead-binding carrier protein in rat epidermis using210Pb

To verify the usefulness of hair as an indicator of²¹⁰Pb and¹⁰⁹Cd accumulation in rats their distribution in different organs were determined. Whereas the radioactivity following²¹⁰Pb i.p. administration after seven days is extremely diminished to compare with that after two days, a considerable accumulation with time of¹⁰⁹Cd was observed under similar experimental conditions. The binding of lead in rat epidermis and hair was investigated and relatively tightly bound²¹⁰Pb to extracted proteins was established. By electrophoretic analysis of epidermal proteins using PAGE-SDS binding of radiolead to a protein carrier with m.w. of about 16 000 was detected. The work was performed in the frame of IAEA Coordinated Research Programme /RC 3673/RB/.     

Time resolved measurements of the electron energy distribution in unstable plasma I. Measurement technique

In this paper the sampling technique for the direct measurement of the second derivative of the Langmuir probe characteristic is described. It enables the study of the variation of the distribution function in the time-unstable plasma. The tests of the method and the discussion of its results are given.The authors desire to acknowledge the support afforded them by Professor Dr. V. Kunzl.     

The output power of 633nm He-Ne lasers

A method is described for establishing the optimum geometry for a 633nm He-Ne laser. For a single-frequency laser, the cavity losses and the choice of tube diameter are critical. For multi-transverse-mode lasers, there exists — for maximum output power — an optimum tube diameter, especially when the cavity loss is high.Based on material originally published in Jemná Mechanika a Optika.     

Highly enantioselective organocatalytic α-selenylation of aldehydes using hypervalent iodine compounds

The highly enantioselective organocatalytic α-selenylation reaction of aldehydes using a hypervalent iodine compound as an oxidative agent from commercially available phenyl diselenide under mild oxidative conditions is described. This transformation affords α-selenyl aldehydes in good yields and with excellent enantioselectivities. By using hypervalent iodine compounds, it opens up a suitable and alternative way for the preparation of biologically active building blocks such as β-hydroxy alcohols, α-amino acids, and α-hydroxy esters.     

Characterization of Gaseous Plasma Sustained in Mixtures of HMDSO and O2 in an Industrial-Scale Reactor

Optical emission spectroscopy and mass spectrometry was used to characterize gaseous plasma in an industrial reactor of volume 5 m³ during deposition of protective coatings. Plasma was created in mixtures of hexamethyldisiloxane (HMDSO) and oxygen at the powers between 1 and 8 kW. The plasma density was somehow below 10¹⁴ m^?3. The flows of both gases were varied up to 200 sccm while the effective pumping speed was adjusted by changing the roots pump rotation speed between 250 and 4000 rpm. At such conditions the HMDSO was only partially dissociated to fragments. The behaviour of optical emission lines and mass ion currents was well correlated indicating that even one single technique was sufficient to monitor the behaviour of plasma at various discharge conditions. The optical emission spectroscopy as a simple and economic method is therefore suitable for controlling key processing parameters in such a plasma reactor.

     

Mechanisms Involved in the Modification of Textiles by Non-Equilibrium Plasma Treatment

Plasma methods are often employed for the desired wettability and soaking properties of polymeric textiles, but the exact mechanisms involved in plasma–textile interactions are yet to be discovered. This review presents the fundamentals of plasma penetration into textiles and illustrates mechanisms that lead to the appropriate surface finish of fibers inside the textile. The crucial relations are provided, and the different concepts of low-pressure and atmospheric-pressure discharges useful for the modification of textile’s properties are explained. The atmospheric-pressure plasma sustained in the form of numerous stochastical streamers will penetrate textiles of reasonable porosity, so the reactive species useful for the functionalization of fibers deep inside the textile will be created inside the textile. Low-pressure plasmas sustained at reasonable discharge power will not penetrate into the textile, so the depth of the modified textile is limited by the diffusion of reactive species. Since the charged particles neutralize on the textile surface, the neutral species will functionalize the fibers deep inside the textile when low-pressure plasma is chosen for the treatment of textiles.