Studies of porous polymer gels. I. One-step suspension technique for preparation of moderately crosslinked methacrylic acid gels

A new method of preparation of carboxyl cation exchangers directly from methacrylic acid and divinylbenzene is described. A suspension technique with a concentrated aqueous calcium chloride solution as the water phase was used. n-Octane and toluene were inert diluents of the monomers. The copolymers obtained have high ion-exchange capacity (9.6–10.6 mequ./g) and porous structure.     

Review of Psychology: The unity of human behavior.

Reviews the book "Psychology: The unity of human behavior," by Timothy J. Gannon (see record 1954-06735-000). This volume is an introductory textbook of psychology for college students. In addition to a somewhat different organization of the material and a different emphasis accorded to various topics Gannon's book introduces certain theoretical considerations which are not ordinarily found in most textbooks. The book is divided into four parts: The first part, the shortest, is a general introduction. The second, entitled "Reception," deals with sensation and perception. The author, in discussing perception, particularly stresses the neural correlates of perception and the localization of functions in the brain. The third, "Response," contains the discussion of reflexes, drives, and emotions. The fourth and last part, "Integration," is the longest, constituting almost half of the book. The principal concern of the author is to present all experiences, and all behavior, as integrated manifestations of a single living person. The entire book is characterized by an effort to present to the student not merely a survey of psychological problems and known facts about man but to provide him at the same time with a concept of man's nature which would serve as a key to the understanding of man as such. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The thermal behaviour of lignins modified by chlorophosphazenes

The thermal behaviour in air of lignins modified by chlorophosphazenes as well as that of the raw materials of lignins has been investigated using thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). The thermogravimetry and derivative thermogravimetry studies of lignins modified by chlorophosphazenes have shown their thermal resistance to be relatively higher than that of the intital raw materials of lignins in concrete kraft lignin and sodium ligninosulfonate. The differential thermal studies have demonstrated that the thermal degradation of products investigated takes place via exothermic processes. The lignins modified by chlorophosphazenes have been shown to be thermal and flame-resistant materials.     

Thin plate elements with relaxed Kirchhoff constraints

An analysis of thin plates by C⁰ elements is presented. The fundamental part of it is the formulation of a set of constraints that relate the rotational degrees of freedom to the translational degrees of freedom and which are weaker than the usual Kirchhoff constraints. A penalty term associated with these constraints is then introduced instead of the usual expression for the shear strain energy. It is shown that the approach is effective for both quadrilateral and triangular elements.     

Surface-tension-induced interfacial convection and its effect on rates of mass transfer

Surface-tension-induced interfacial convection (Marangoni phenomena) can appear as a result of mass and heat transfer, compression and dilatation of surface films or their non-Newtonian behaviour and owing to presence in the interface of electrostatic charges. In process engineering problems the mass transfer effect is usually predominant and, depending on the geometry of the system, leads to surface renewal or changes in interfacial area. The surface renewal phenomena can appear as instabilities or disturbances and their effect on mass transfer is presented for transfer to and from drops as well as across flat interfaces in stirred and laminar flow contactors. Mass transfer coefficients and drag coefficients of drops are compared under conditions of undisturbed (diffusional) transfer, cellular convection and interfacial turbulence for stable and unstable direction of transfer. The importance of gravitational instability is indicated.     

Effect of reactive ion etch-induced damage on the performance of 4H-SiC schottky barrier diodes

The effect of reactive ion etch (RIE) induced damage on 4H-SiC surfaces etched in fluorinated plamas has been investigated and characterized using Ni Schottky diodes and x-ray photoelectron spectroscopic surface analysis. The diodes were characterized using current-voltage, current-voltage-temperature, and capacitance-voltage measurements with near ideal forward characteristics (n=1.07) and forward current density as high as 9000 A/cm² from the control (unetched) devices. High current handling capability was observed in diodes with etched surfaces as well. Diodes with surfaces etched in CHF₃ containing plasmas showed a significant reduction in the barrier height compared to the diodes with surfaces etched in CF₄ containing plasma. Control devices exhibited high leakages when reverse biased, which is attributed to the presence of a thin (∼2 nm) oxide layer at the metal-semiconductor interface. However, under reverse bias diodes with CHF₃-etched surfaces showed improvement in leakage current compared to diodes with CF₄-etched surfaces and the control diodes.     

Evaluating ovarian reserve: follicle stimulating hormone and oestradiol variability during cycle days 2-5

A prospective measurement of follicle stimulating hormone (FSH) and oestradiol between cycle days 2 and 5 was conducted to investigate the intra- and inter-cycle variability in a healthy population of women with regular menstrual intervals. Daily serum samples were obtained from 44 women for a total of 66 cycles on cycle days 2, 3, 4 and 5. FSH concentrations were consistent on all cycle days measured. Oestradiol concentrations on cycle day 2 were not different from cycle day 3, but concentrations on cycle day 4 and cycle day 5 were statistically different from both cycle day 2 and cycle day 3 by analysis of variance (P < or = 0.05). Evaluation of functional ovarian reserved by cycle day 3 FSH measurement has become the standard in most assisted reproductive technology programmes. The recent change in FSH standardization coupled with the inflexibility of cycle day 3 testing has led to a re-evaluation of testing protocols. Cycle day 3 appears to have emerged as a dictum because most ovulation induction protocols are initiated on cycle day 3, 4 or 5. Flexibility of sampling day can be introduced as suggested by these results. The additional information ascertained from oestradiol testing as applied to evaluation of ovarian reserve warrants further investigation.     

Synergy and resistance to synergy between beta-lactam antibiotics and glycopeptides against glycopeptide-resistant strains of Enterococcus faecium

A synergistic effect between vancomycin or teicoplanin and different beta-lactam antibiotics was found for two strains of Enterococcus faecium, EFM4 and EFM11, expressing resistance to glycopeptides and belonging to the VANA class. The MICs of penicillin for these two strains were 16 and 128 micrograms/ml, respectively. By using a penicillin-binding protein (PBP) competition assay, it was shown that the affinities of PBPs for different beta-lactam antibiotics and the MICs of these antibiotics obtained in the presence of teicoplanin correlated with the substitution of two high-molecular-weight PBPs for the low-molecular-weight PBP5 as the essential target. Mutants of EFM4 and EFM11 which had lost the synergistic effect between beta-lactams and glycopeptides were selected on teicoplanin plus ceftriaxone at a frequency of 10(-5) and 10(-3), respectively. The mechanism of the loss of synergy was explored. For the mutants derived from EFM4, it was associated with a change in PBPs, while for the mutants derived from EFM11, it was related to some unknown change on the conjugative plasmid responsible for the glycopeptide resistance. These combined observations reflect the relationship which seems to exist between the new D-lactate peptidoglycan precursor, synthesized when the vancomycin resistance is expressed, and the affinity of the different PBPs for this precursor.