Studies on the optimal immunization schedule of the mouse as an experimental animal. The effect of antigen dose and adjuvant type

This study was undertaken to establish the optimal immunogen dose for immunization of mice, using a viomycin-protein conjugate as a hapten immunogen. It was found that specific immunoglobulin G (IgG) formation depends on both the dose of antigen and the type of adjuvant: the optimal antigen dose for an immune response is quite different depending on whether the mice are being treated with Freund's complete adjuvant (FCA) or Freund's incomplete adjuvant (FICA). The total IgG amount depends mainly upon the type of adjuvant used. FCA gave the double the level of IgG compared to that obtained with FICA. The antigen dose was found to have little influence on the total production of IgG. Mice given a primary immunization with 10 micrograms of antigen emulsified in FCA and then given a booster with the same amount of antigen emulsified in FICA produced a strikingly high level of specific anti-viomycin antibody of over 2.5 mg/ml of the antiserum. It was also found that decreases in the weight of the mice were related to the kind of adjuvant used as well as to the level of the specific antibody formed.     

Studies on the optimal immunization schedule of experimental animals. IV. The optimal age and sex of mice, and the influence of booster injections

To establish the optimal condition for preparing mouse antiserum specific to a drug, the optimal age and sex of mice for the immune response were studied by measuring the mouse serum levels of total immunoglobulin G (IgG) and specific antibody to viomycin, as well as the changes in weight of mice immunized with a viomycin immunogen. It was observed that age was a more important factor than sex, and strongly affected productions of both total and specific IgGs of mice. The mice aged 8 weeks yielded the highest levels of both total IgG and the specific antibody. In the study on the influence of booster schedule, the number of boosters given had a larger influence on the immune response than the interval between priming and boosters. The greater the number of booster shots given, the less was the production of total and specific antibodies. The decrease in the weight of mice after immunization was also studied in more detail; it was found that it only occurred in the first week after priming but not after a booster injection. The mice aged eight weeks showed the largest weight loss.     

Studies on the optimal immunization schedule of experimental animals. V. The effects of the route of injection, the content of Mycobacteria in Freund's adjuvant and the emulsifying antigen

The effects of several conditions for the immunization of mice was studied using an aliquot of a viomycin (VM) protein conjugate as the common primary or booster antigen. Responses of the mice were assessed by measuring mouse serum levels of total immunoglobulin G (IgG) and anti-VM antibody responses using the newly improved two assay methods. The choice of route was found to be a very important factor in immunization and intraperitoneal injection was the most optimal among the four routes studied. The effect of the concentration of Mycobacteria in Freund's complete adjuvant (FCA) was also studied, and it was found that a diluted FCA was more effective than a commercial FCA. The effect of the controlled release of the antigen was studied and three important phenomena were observed: The mice immunized by the mini-osmotic pump-aided controlled release of the antigen responded with similar small amounts of both total IgG and anti-VM antibody regardless of the presence or absence of FCA in the antigen; emulsifying the antigen with FCA was a very important condition for the effective elicitation of the specific antibody; a mixture of antigen and FCA without emulsifying produced little specific antibody and a large amount of total IgG. The more effectively immunized mice responded with a larger decrease in body weight soon after the primary injection.     

Oxidation of polyethylene under irradiation at low temperature and low dose rate. Part II. Low temperature thermal oxidation

This paper deals with the kinetic modelling of unstabilised polyethylene thermal oxidation, particular attention being paid to the domain of low temperatures, typically below 80 °C. Experimental data show that the temperature dependence of the induction time t_i and the steady state rate of oxygen absorption r_S display a discontinuity at 80 °C. A model based on the hypothesis that this discontinuity concerns only the PO₂ bimolecular combination processes and is essentially explained by the competition between terminating and non-terminating PO₂ + PO₂ reactions, was proposed. With pertinent values of the Arrhenius parameters of the elementary reactions under consideration, the model fits well the experimental data (in the 40-200 °C temperature range) and is consistent with previously analysed results of radiochemical ageing. According to this model, 35-40% of the bimolecular PO₂ combinations would not be terminating at 45 °C and this proportion would increase with the temperature. Concerning terminations, the relative fraction of coupling processes, leading to peroxide bridges, would decrease relatively to the disproportionation processes when the temperature increases.     

细胞动力学研究VI. 厌氧菌生长过程热化学特征

用LKB2277生物活性检测系统测定了三种厌氧菌---吉氏类杆菌、艰难梭状芽胞杆菌、黑色消化球菌的生长发热功率曲线。根据广义logistic方程, 建立了细菌生长过程的热动力学方程:ln[P/(Pm-P)^v^+^1]=ln[P0/(Pm-P0)^v^+^1]+k.t。由此热动力学方程, 求得了细菌的生长常数k, 根据Arrhenius公式求得吉氏菌的生长活化能Ea=59.7kj/mol, 应用过渡态理论得到吉氏菌在不同温度下的活化力学参数, 这个热动力学方程描述的是一系列不规则的细菌生长过程发热曲线, 将它与经典的指数模型和logistic模型进行比较, 它具有更广泛的适用性。     

Studies on the repassivation behavior of aluminum and aluminum alloy exposed to chromate solutions

This study explores the repassivation ability of a scratch in a chromate conversion coating (CCC) on aluminum alloy, AA2024‐T3, and hence evaluates the theory of migration of hexavalent chromium ions from the protected surface of the aluminum alloy to the exposed surface. To confirm that protection was indeed restored by hexavalent chromium ions, the repassivation of a scratch on pure aluminum exposed to a dichromate solution was studied. This forms the simplest subsystem model of the CCC on the alloy in which the CCC is replaced by pure hexavalent chromium and alloy with pure aluminum. Open‐circuit potential measurements, synchrotron infrared microspectroscopy (SIRMS) and secondary ion mass spectroscopy (SIMS) have been used judiciously to evaluate the repassivation behavior. Results indicate that the dichromate ions have high mobility. The slow migration of Cr(VI) ions from the protected surface to the scratch is observed to result in repassivation, as seen from the steady increase in the potential in 0.05 M NaCl solution. The results obtained from SIMS and SIRMS confirm the migration of the oxyanions from the protected region to the metal surface exposed by the scratch. The SIRMS results indicate the formation of an Al(III)–Cr(VI) complex, proposed and shown to be formed in the pits. Copyright © 2003 John Wiley & Sons, Ltd.     

Studies on the preparation and characterization of monodisperse polystyrene latices. VI. Preparation of zwitterionic latices

The preparation of zwitterionic latex particles is reported by using a mixed anionic and cationic initiator system without requiring surface-active agents. Isoelectric points were found from microelectrophoresis experiments and were in the pH range of 3.5-5. Close to the isoelectric point, the latices coagulated as expected, and good stability was achieved outside this narrow range. This range of stability was in good agreement with predictions from current theory. Redispersion after coagulation was found to be difficult as was expected for a hydrophobic colloid. The electrokinetic behavior did not result in the maximum in zeta potential at an electrolyte concentration of 1 mM unlike the situation for other hydrophobic polystyrene latex particles, and hence these systems may be even better models for other colloidal studies.     

Studies on the influence of various experimental conditions on electrochemical generation of ferrate(VI) in NaOH-KOH mixed electrolyte

Ferrate(VI) was prepared by electrooxidation in diaphragm electrolyzer with iron wire gauze as anode and NaOH-KOH mixed solution as electrolyte. The influences of various experimental conditions, such as the volume ratio of NaOH-KOH mixed electrolyte, temperature, current density, passivation of iron anode were investigated on ferrate current efficiency. Due to the low solubility of K₂FeO₄ in concentrated alkaline solution and the passivation of iron wire gauze anode, a highest current efficiency over 90% was obtained at 45°C and at a current density of 5 mA cm⁻² in mixed electrolyte with the volume ratio of NaOH: KOH equal to 6: 4. The result is superior to using NaOH and KOH as electrolyte respectively. In addition, polarization curves, scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) were employed to further study the effects of synthesis conditions on ferrate(VI) in theory. Published in Russian in Elektrokhimiya, 2009, Vol. 45, No. 7, pp. 853–857. The article is published in the original.     

Oxidation of polyethylene under irradiation at low temperature and low dose rate. Part I. The case of “pure” radiochemical initiation

As part of a study on the kinetic modelling of polyethylene oxidation under irradiation at low temperature and low dose rate, this first part deals with the kinetic regime in which thermal initiation, linked to hydroperoxide decomposition, is negligible compared to radiochemical initiation due to polymer radiolysis. The kinetic analysis is based on results published 30 years ago by Decker, Mayo and Richardson. A small modification of their mechanistic scheme, consisting in the introduction of a non-terminating bimolecular combination of PO₂ radicals, leads to a more consistent set of radiochemical yield values. The most significant change is a decrease in the radiochemical yield of radicals G_i from 10 to 8. At 45 °C, termination of PO₂ radicals is not very efficient: 35-40% of the PO₂ + PO₂ encounters are non-terminating, 75% of the termination events lead to peroxide bridges, the rest is a disproportionation according to the Russell mechanism.     

Studies on polymers containing functional groups. VI. Kinetics of the polymerization and copolymerization behaviors of o-hydroxystyrene

Some kinetic studies were made of the homopolymerization of o-hydroxystyrene and its copolymerization behavior with styrene and methyl methacrylate in tetrahydrofuran using azobisisobutyronitrile as initiator were done. The rate of polymerization experimentally obtained is given by R_p = K[M][I]^0.72. Accordingly, it is likely that the growing chain radicals are terminated not only by mutual termination but also by a chain-transfer mechanism, the latter occupying a considerable portion. The latter is mostly attributed to the transfer to monomer, i.e., C_m for o-hydroxystyrene was 1.3 × 10^?2. Some transfer mechanisms were assumed, although it is difficult to elucidate the mechanism in detail, owing to its complexity. Effects of solvent on the rate of polymerization were examined, dioxane, methyl ethyl ketone, ethanol, and tetrahydrofuran being used. However, no differences were found among the solvents. The apparent activation energy of polymerization was found to be 21.5 kcal./mole. Monomer reactivity ratios and Alfrey-Price Q–e values for o-hydroxystyrene were determined. The Q–e values (Q = 1.41, e = ?1.13) are rather similar to those of p-methoxystyrene. Thus, the e value for o-hydroxystyrene is more negative than that for styrene.