Formation of collisionless high-beta plasmas by odd-parity rotating magnetic fields.

Odd-parity rotating magnetic fields (RMFo) applied to mirror-configuration plasmas have produced average electron energies exceeding 200 eV at line-averaged electron densities of approximately 10(12) cm-3. These plasmas, sustained for over 10(3)tauAlfven, have low Coulomb collisionality, vc* triple bond L/lambdaC approximately 10(-3), where lambdaC is the Coulomb scattering mean free path and L is the plasma's characteristic half length. Divertors allow reduction of the electron-neutral collision frequency to values where the RMFo coupling indicates full penetration of the RMFo to the major axis.

Development of process equipment to separate nonthermal and thermal effects of RF energy on microorganisms.

We developed a modified radio frequency (RF) dielectric heater, as a component of a continuous process, for isolating thermal and nonthermal effects of RF energy on microorganisms in liquid foods. The concept combines instantaneous input of RF energy to the food system with rapid removal of thermal energy. We used a double tube heat exchanger as an integral part of the RF heater. The outer tube was Teflon. The inner tube was stainless steel which was grounded in the RF circuit. Product flowed through the annular region between the two concentric tubes. Cooling water flowed through the grounded stainless steel tube. The RF energy was absorbed by the process fluid in the annular region. The cooling water flowing in the inner tube removed the thermal energy from the process fluid controlling the temperature.

Acarbose, a pseudooligosaccharide, is transported but not metabolized by the maltose-maltodextrin system of Escherichia coli.

The pseudooligosaccharide acarbose is a potent inhibitor of amylases, glucosidases, and cyclodextrin glycosyltransferase and is clinically used for the treatment of so-called type II or insulin-independent diabetes. The compound consists of an unsaturated aminocyclitol, a deoxyhexose, and a maltose. The unsaturated aminocyclitol moiety (also called valienamine) is primarily responsible for the inhibition of glucosidases. Due to its structural similarity to maltotetraose, we have investigated whether acarbose is recognized as a substrate by the maltose/maltodextrin system of Escherichia coli. Acarbose at millimolar concentrations specifically affected the growth of E. coli K-12 on maltose as the sole source of carbon and energy. Uptake of radiolabeled maltose was competitively inhibited by acarbose, with a Ki of 1.1 microM. Maltose-grown cells transported radiolabeled acarbose, indicating that the compound is recognized as a substrate. Studying the interaction of acarbose with purified maltoporin in black lipid membranes revealed that the kinetics of acarbose binding to LamB is asymmetric. The on-rate of acarbose is approximately 30 times lower when the molecule enters the pore from the extracellular side than when it enters from the periplasmic side. Acarbose could not be utilized as a carbon source since the compound alone was not a substrate of amylomaltase (MalQ) and was only poorly attacked by maltodextrin glucosidase (MalZ).

Concentration-dependent elicitation of dermal sensitization in guinea pigs treated with 2,4-toluene diisocyanate.

2,4-Toluene diisocyanate (TDI) can cause pulmonary sensitization and allergic skin reactions. Since many commercial materials contain TDI, the present study was designed to determine the concentration-dependent elicitation of dermal sensitization in guinea pigs treated with TDI. Young adult guinea pigs received two open, epicutaneous induction applications (25 microliters) of 8,20, or 40% TDI in n-butyl ether on two separate areas. Five days later, animals were challenged with 0.0, 0.025, 0.05, 0.1, 0.2, and 0.4% TDI (25 microliter per concentration site). All challenge applications except the 0.0% solution elicited a positive response in 75 to 100% of the animals, and the severity of the skin reactions was dependent on the concentrations of the challenge and induction application. In another study at lower doses, animals received a total induction application (25 microliters per each of two sites) of either 4 or 8% TDI and were challenged with 0.0, 0.006, 0.012, 0.025, 0.05, and 0.1% of TDI (25 microliters per site). TDI did not elicit a sensitization response at challenge concentrations up to 0.012% (total application of 3 micrograms) when a 4% induction application was used, while a challenge concentration of 0.025% (total application of 6.25 micrograms) elicited a sensitization response in 63% of the animals. At the 8% induction application (total application of 4000 micrograms), all challenges, except the 0.0% indicated sensitization, and the intensities of the skin reactions were correlated with the challenge concentrations and the induction application. In conclusion, the results demonstrate that TDI produced sensitization at dilute induction concentrations and that the severity of the dermal response was correlated with the concentration used at induction and challenge. Furthermore, no observed effect levels were determined below which the challenge concentration did not elicit a dermal hypersensitivity reaction. When 4% TDI was applied at induction, no observed effect was seen with a dermal challenge application of 3 micrograms whereas an effect was seen with 6.25 micrograms (in 25 microliters) when n-butyl ether was the solvent.