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Background: The CDC and ACIP recommend COVID-19 vaccination for patients with inborn errors of immunity (IEI). Not much is known about vaccine safety in IEI, and whether vaccination attenuates infection severity in IEI., Objective: To estimate COVID-19 vaccination safety and examine effect on outcomes in patients with IEI., Methods: We built a secure registry database in conjunction with the US Immunodeficiency Network to examine vaccination frequency and indicators of safety and effectiveness in IEI patients. The registry opened on January 1, 2022, and closed on August 19, 2022., Results: Physicians entered data on 1245 patients from 24 countries. The most common diagnoses were antibody deficiencies (63.7%). At least one COVID-19 vaccine was administered to 806 patients (64.7%), and 216 patients received vaccination prior to the development of COVID-19. The most common vaccines administered were mRNA-based (84.0%). Seventeen patients were reported to seek outpatient clinic or emergency room care for a vaccine-related complication, and one patient was hospitalized for symptomatic anemia. Eight hundred twenty-three patients (66.1%) experienced COVID-19 infection. Of these, 156 patients required hospitalization (19.0%), 47 required ICU care (5.7%), and 28 died (3.4%). Rates of hospitalization (9.3% versus 24.4%, p < 0.001), ICU admission (2.8% versus 7.6%, p = 0.013), and death (2.3% versus 4.3%, p = 0.202) in patients who had COVID-19 were lower in patients who received vaccination prior to infection. In adjusted logistic regression analysis, not having at least one COVID-19 vaccine significantly increased the odds of hospitalization and ICU admission., Conclusion: Vaccination for COVID-19 in the IEI population appears safe and attenuates COVID-19 severity., (© 2024. The Author(s).)

Food protein-induced allergic proctocolitis (FPIAP) is a non-IgE-mediated allergic condition that presents with hematochezia in otherwise healthy infants. It is most commonly induced by cow's milk protein via breast milk or formula. The prognosis for FPIAP is generally considered favorable with most infants achieving symptomatic resolution after diet modification. Most infants go on to tolerate the offending foods by 1-3 years of age. Over 8 years at our institution, five patients were identified and noted to have FPIAP to cow's milk during infancy with subsequent development of IgE-mediated allergic reaction to cow's milk and other foods. All five cases developed other atopic disorders (atopic dermatitis in four cases). IgE-mediated cow's milk allergy has persisted beyond the preschool years in at least two patients (currently 8 and 16 years old). For three of the patients, the IgE-mediated reaction to cow's milk was severe with development of anaphylaxis or angioedema. In addition, three patients experienced anaphylaxis or angioedema to allergens other than milk. While FPIAP is a non-IgE-mediated process traditionally thought not to progress past the first year of life, some infants with FPIAP develop severe, persistent IgE-mediated cow's milk allergy. To our knowledge, this is the first detailed clinical description of such patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Tran, Wisner, Jeha and Wall.)

Primary immunodeficiency is a group of disorders associated with susceptibility to infectious agents and the development of various comorbidities. Many primary immunodeficiencies are complicated by immune dysregulation, autoinflammation, or autoimmunity which impacts multiple organ systems. Major advances in the treatment of these disorders have occurred over the last half-century, and deeper molecular understanding of many disorders combined with clinically available genetic testing is allowing for use of precision therapy for several primary immunodeficiencies. Patients with antibody deficiencies who rely on immunoglobulin replacement therapy now have many treatment options with products that are much safer and better tolerated compared to the past. Newborn screening for severe combined immunodeficiency, now implemented throughout the USA and in many countries worldwide, has lowered the age at which many patients are diagnosed with these diseases. Early diagnosis of severe combined immunodeficiency allows infants to proceed to definitive therapy such as stem cell transplantation or gene therapy prior to facing potentially life-threatening infections. While stem cell transplantation continues to carry significant risks, knowledge gained over recent decades is allowing for improved survival with less toxicity and less graft versus host disease., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage., (Copyright © 2020 Wall, Wisner, Gipson and Sorensen.)

An 8-year-old male from south Louisiana was diagnosed with Loeffler syndrome of suspected Ascaris origin. Further investigation of the farm recovered larvated, infective Ascaris eggs from the soil in drains surrounding pens on the family's small hog farm. Molecular analysis of the recovered eggs, in conjunction with Ascaris-specific IgE, inadequate farm management and sanitation, and behavioral risk factors indicate the patient had an Ascaris suum soil-transmitted infection.

Patients with specific antibody deficiency (SAD) have a deficient immunologic response to polysaccharide antigens. Such patients experience sinopulmonary infections with increased frequency, duration, or severity compared with the general population. SAD is definitively diagnosed by immunologic challenge with a pure polysaccharide vaccine in patients 2 years old and older who have otherwise intact immunity, using the 23-valent pneumococcal polysaccharide vaccine as the current gold standard. Specific antibody deficiencies comprise multiple immunologic phenotypes. Treatment must be tailored based on the severity of symptoms. Most patients have a good prognosis. The deficiency may resolve over time, especially in children., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background and Aims: Cholecystokinin-cholescintigraphy (CCK-CS) provides a physiologic, noninvasive, and quantitative method for assessing gallbladder contraction and calculation of a gallbladder ejection fraction (GBEF). At present, it is used most commonly to identify patients with suspected functional gallbladder disorder. However, the methodology of CCK infusion and normal values differ markedly among imaging centers., Methods: This document represents the consensus opinion of an interdisciplinary panel that gathered to assess the current optimal method for performing CCK-CS in adults, potential uses and limitations of CCK-CS, and questions that require further investigation., Results: The panel recommended the use of a single, standardized, recently described CCK-CS protocol that involves infusion of 0.02 μg/kg of sincalide over 60 minutes with a normal GBEF defined as ≥38%. The panel emphasized the need for a large, multicenter, prospective clinical trial to establish the utility of CCK-CS in the diagnosis of functional gallbladder disease. Although not without controversy regarding its clinical utility, the primary indication for CCK-CS at present is the well-selected patient with suspected functional gallbladder disorder., Conclusion: Agreement was reached that the adoption of this standardized protocol is critical to improve how CCK-CS is used to direct patient care and will represent an improvement over the diverse methods currently in use by eliminating the current lack of uniformity and adding both reliability and credibility to the results.

Background & Aims: Cholecystokinin-cholescintigraphy (CCK-CS) provides a physiologic, noninvasive, and quantitative method for assessing gallbladder contraction and calculation of a gallbladder ejection fraction (GBEF). At present, it is used most commonly to identify patients with suspected functional gallbladder disorder. However, the methodology of CCK infusion and normal values differ markedly among imaging centers., Methods: This document represents the consensus opinion of an interdisciplinary panel that gathered to assess the current optimal method for performing CCK-CS in adults, potential uses and limitations of CCK-CS, and questions that require further investigation., Results: The panel recommended the use of a single, standardized, recently described CCK-CS protocol that involves infusion of 0.02 μg/kg of sincalide over 60 minutes with a normal gallbladder ejection fraction defined as ≥38%. The panel emphasized the need for a large, multicenter, prospective clinical trial to establish the utility of CCK-CS in the diagnosis of functional gallbladder disease. Although not without controversy regarding its clinical utility, the primary indication for CCK-CS at present is the well-selected patient with suspected functional gallbladder disorder., Conclusions: Agreement was reached that the adoption of this standardized protocol is critical to improve how CCK-CS is used to direct patient care and will represent an improvement over the diverse methods currently in use by eliminating the current lack of uniformity and adding both reliability and credibility to the results., (Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Four distinct factors in extracts from murine erythroleukemia (MEL) cells interacted with the human beta-globin gene promoter CAAT box: CP1, GATA-1, and two novel factors, denoted a and b, one of which is highly inducible in the MEL system. GATA-1 binding to the CAAT element was very unstable (half-life < 1 min), whereas bindings of a, b, and CP1 were comparatively stable, with half-lives of 18, 19, and 3.5 min, respectively. Stable transfections of MEL cells showed that in the presence of the beta-globin locus control region (LCR), the wild-type CAAT box, a mutant which bound to GATA-1 with increased stability over the normal sequences, and a mutant which bound a, b, and CP1 specifically could all stimulate transcription greater than ninefold over that induced by a null CAAT mutation in both uninduced and terminally differentiated MEL cells. A mutant which bound the a and b factors specifically gave only a twofold stimulation of promoter activity, and this lower activity correlated with a decrease in the stability of binding of the b protein. On the other hand, CP1 binding alone did not stimulate transcription. Taken together, these results suggest that in the context of the wild-type beta-globin CAAT element the b factor stimulates transcription directed by the LCR in MEL cells, although the LCR can also function through more stable GATA-1-binding sequences. However, in K562 cells, the wild-type beta-globin CAAT box alone was unable to stimulate gene expression directed by the LCR and high levels of transcription were obtained only upon inclusion of more upstream beta-globin promoter sequences. In contrast, a construct containing only the A gamma-globin CAAT box region did give high expression levels in K562 cells. Thus, there is a fundamental difference in the way the LCR functions in these two model systems in terms of its requirements at the promoter level.

Seventy incontinent female patients were diagnosed as having unstable bladders during a two-year period. The diagnosis was made with a questionnaire, carbon dioxide urethroscopy and pressure profiles according to the technique of Robertson. Forty patients were continent on medication, 11 were improved, 6 showed no improvement, 1 was on a trial of medication at this writing, and 12 were lost to follow-up. The medical management and various drugs used in the treatment of unstable bladder are discussed in this report.

Glass transition measurements on monodispersed polystyrenes of different molecular weight and their binary mixtures result in the following conclusions: (a) the effect of molecular weight on the glass transitions of monodispersed samples satisfies the Fox and Flory equation written as T g = T g ∞ - A / M n , with constant A = 0.84 × 10 -5 ; (b) polymers of the same number average molecular weight with a broad distribution show lower glass transitions than the monodispersed; (c) the binary mixtures follow the Gordon-Taylor equation derived for copolymers, with constant k (experimental) 0.5.

Incubation of soluble extracts from Vibrio harveyi with [3H]tetradecanoic acid (+ ATP) resulted in the acylation of several polypeptides, including proteins with molecular masses near 20 kilodaltons (kDa), and at least five polypeptides in the 30- to 60-kDa range. However, in growing cells pulse-labeled in vivo with [3H]tetradecanoic acid, only three of these polypeptides, with apparent molecular masses of 54, 42, and 32 kDa, were specifically labeled. When extracts were acylated with [3H] tetradecanoyl coenzyme A, on the other hand, only the 32-kDa polypeptide was labeled. When luciferase-containing dark mutants of V. harveyi were investigated, acylated 32-kDa polypeptide was not detected in a fatty acid-stimulated mutant, whereas the 42-kDa polypeptide appeared to be lacking in a mutant defective in aldehyde synthesis. Acylation of both of these polypeptides also increased specifically during induction of bioluminescence in V. harveyi. These results suggest that the role of the 32-kDa polypeptide is to supply free fatty acids, whereas the 42-kDa protein may be responsible for activation of fatty acids for their subsequent reduction to form the aldehyde substrates of the bioluminescent reaction.

Preferential cleavage of Saccharomyces cerevisiae chromosomes in internucleosomal (linker) regions and nonspecific degradation of chromatin by an anticancer antibiotic which degrades DNA were investigated and found to increase in consecutive stages of growth. Cleavage of DNA in internucleosomal regions and intensities and multiplicities of nucleosomal bands were dependent on drug concentration, growth phase of the cells, and length of incubation. Cellular DNA was least degraded during logarithmic phase. After cells progressed only one generation in logarithmic phase, low concentrations (6.7 x 10(-7) to 3.4 x 10(-6) M) of bleomycin produced approximately three to seven times more DNA breaks. Internucleosomal cleavage was highest, and the most extended oligonucleosomal series and extensive chromatin degradation were observed during stationary phase. It is concluded that the growth phase of cells is critical in determining amounts of the highly preferential cleavage in internucleosomal regions and overall breakage and degradation of DNA. Mononucleosomal bands were most intense, indicating the greatest accumulation of DNA of this size. Mean mononucleosomal lengths were 165.9 +/- 3.9 base pairs, in agreement with yeast mononucleosomal lengths. As high-molecular-weight chromatin was digested by bleomycin, oligonucleosomes and, eventually, mononucleosomes became digested. Therefore, it is also concluded that bleomycin degradation of oligonucleosomes and trimming of DNA linker regions proceed to degradation of the monosomes (core plus linker DNA).

Pyrolysis of monodisperse poly- α -methylstyrene of wide molecular weight range (M:25,000-5,000,000) was studied isothermally under vacuum in the temperature range 240-280 °C. Thermogravimetric analysis was used for measuring the rate of degradation, and gel permeation chromatography for analyzing the molecular weight and molecular weight distribution as a function of conversion. The initial rate of monodisperse poly- α -methylstyrenes, and the deuterated samples (poly- α -trideuteromethyl- β, β -dideuterostyrene) increases with increasing molecular weight. At molecular weight higher than 1 × 10 6 , the initial rate continues to increase almost linearly instead of being constant as concluded from earlier work. The molecular weight distribution ratio, M w /M n , increases as a function of conversion and approaches the most probable distribution. The results conform to a degradation mechanism with random initiation. The curves of initial rate as a function of molecular weight lead to higher zip lengths than previous estimates. Attempts at simultaneous estimation of zip length and transfer constant from the rate and molecular weight data led to inconsistent results. If the variation of termination rate with molecular weight plays a role, this variation must be less than that derived naively from melt viscosity. Bimodal molecular weight distributions were not found.

The mass spectra of tetramethylphosphinoborine trimer, [P(CH 3 ) 2 B(CH 3 ) 2 ] 3 (I) and a a compound, P 5 (CH 3 ) 9 B 5 H 9 , (II) prepared from dimethylphosphinoborine were observed, and the compounds were pyrolyzed at 300 to 500° C. Most peaks in the spectrum of (I) came from the P-B, B-C, and P-C cleavages. The mass spectrum of (II) was much more complicated with evidence for methyl group redistribution. The pyrolysis of both compounds indicates a very complicated mechanism with many unidentifiable compounds. Trends in the formation of volatile products indicate that both compounds are completely decomposed in 4 hr at 450° C. Compound (I) produces trimethylboron, which disappears rapidly above 400° C. Neither (I) nor (II) formed ethane or elemental phosphorus.

The direct replacement of aromatic fluorine in hexafluorobenzene has hitherto been possible only by the use of nucleophilic reagents. In this investigation, the replacement of nuclear fluorine by nonnucleophilic, or weakly nucleophilic, reagents was achieved by reaction at relatively high temperatures, 300 to 850 °C. For example, the reaction of hexafluorobenzene with such reagents as bromine, chlorine, and tetrafluoroethylene gave as major products bromopentafluorobenzene, chloropentafluorobenzene, and octafluorotoluene. In addition, pentafluorohalobenzenes can also be produced by passage of hexafluorobenzene over the appropriate alkali or alkaline earth-metal halides at elevated temperatures. The mechanism of the pyrolytic reactions of hexafluorobenzene and the nonionic coreactants are considered to involve free-radical intermediates. The reaction of hexafluorobenzene with the ionic coreactants may proceed by an ionic mechanism similar to that advanced for the usual, relatively low-temperature, nucleophilic substitution reactions of aromatic systems. However, a more complicated free radical-ionic process cannot be ruled out for these reactions.

A study has been made of the effect of drying and purification of polycaprolactam (nylon-6) on its thermal decomposition. The conclusions drawn from previous work, that a hydrolytic mechanism is at least partially operating due to the presence of water and acid polymerization catalysts, are confirmed. Purification of the material decreases the rate of degradation and the production of CO 2 , and increases the preexponential factor and the activation energy. The hydrolytic decomposition, which competes with the thermal free-radical degradation process, would be expected to produce carboxylic acids and amines, the former decomposing further to form CO 2 . The preexponential factor is increased by sample purification from 10 7 to 10 10 and the activation energy from 34 to 43 kcal/mole. The decomposition behavior of the purest sample is a nearly perfect example of the random decomposition of linear polymer chains. All other samples of polyamides thus far studied also appear to decompose by random or nearly random mechanisms.

The rates of volatilization of linear polymers of ethylene and propylene and their copolymers are somewhat characteristic of random degradation in that a maximum occurs in the rate curve for all polymers studied. Increasing amounts of propylene in the copolymer showed increases in the maximum rate on thermal decomposition. Minute inorganic and organic impurities added to the polypropylene have considerable effect on the thermal stability of the polymer by lowering the rates of volatilization and increasing the activation energy. Possibly there is an inhibition of the free-radical chain process, and the overall reaction becomes more like that for the initiation process. Rate studies and volatile decomposition products for a fully deuterated linear polyethylene were also determined, and its activation energy was calculated to be 70 kcal/mole, which is very close to the value (72 kcal/mole) calculated for the nondeuterated polymer. The effect of a large dose of beta-radiation on a linear polyethylene was also determined. Results suggest that scissions in the chain, as well as cross links, are caused by the radiation.

The thermal decomposition of various fluorocarbon polymers were investigated; volatile products of the decomposition were determined along with the overall rates of volatilization, and from these rates the activation energies were calculated for the thermal degradation reactions. The thermally most stable of all the polymers thus far studied are the completely fluorinated ones. However, evidence from a study of the decomposition of hexafluoropropylene telomers and from the study of a copolymer of tetrafluoroethylene and hexafluoropropylene suggests that the homopolymer of hexafluoropropylene, if it could be made, would be quite unstable. The photoinduced decomposition of polytrifluorochloroethylene was also investigated, and estimates of the activation energies were obtained for the various elementary steps of the decomposition mechanism. The photoinduced experiments indicated that mutual termination of the radical intermediates takes place and that a diffusion effect on depropagation becomes pronounced below 250 °C.

The synthesis of various derivatives of pentafluorophenetole of the type C 6 F 5 OCH 2 CH 2 R is described. The R group was chlorine, bromine, hydroxyl, pentafluorophenoxy, acetoxy, and trifluoroacetoxy. 2-Pentafluorophenoxy-1,1,1-trifluoroethane and 1,1-bis(pentafluorophenoxy)ethane were similarly synthesized. A study was made of the behavior of these ethers toward pyrolysis, acids, and bases. In general, those ethers containing β -hydrogen atoms give pentafluorophenol on pyrolysis. Some compounds, such as 2-pentafluorophenoxyethyl bromide, give rearranged products as well. Under basic conditions, cleavage to pentafluorophenol was observed with aqueous potassium hydroxide, whereas the use of solid potassium hydroxide pellets gives dehydrohalogenated products. Concentrated sulfuric acid causes cleavage of most of the ethers employed. 2-Pentafluorophenoxy-1,1,1-trifluoroethane resists attack both by acids and bases. The synthesis and polymerization of two new vinyl monomers, pentafluorophenyl vinyl ether and 1,2-difluorovinyl pentafluorophenyl ether, are also presented.

The changes in molecular weights, their distributions, and initial rates have been measured, for a series of polystyrenes prepared by thermal and anionic procedures. The information obtained and previous results can be explained to a very large extent by a kinetic chain decomposition comprised of competing end and random initiation, depropagation, intra- and intermolecular transfer and termination by combination.

Mixing of aqueous polymer solutions containing Ti 3+ and H 2 O 2 in a rapid flow mixer produced radicals by abstraction, OH + RH → R · + H 2 O, which were observed by electron spin resonance. Oscillation of segments was sufficient to narrow the lines to 0.5-2.0 g. Polymers and radicals identified with more or less certainty were polyacrylic acid, 〰 CH(CO 2 H)ĊHCH(CO 2 H) 〰 , polymethacrylic acid, 〰 C(CH 3 )(CO 2 H)ĊHC(CH 3 )(CO 2 H) 〰 , polyvinyl alcohol, 〰CHOHĊHCHOH〰, and one indefinite, polyethylene imine, 〰CH 2 ṄCH 2 〰 or 〰CH 2 ṄOCH 2 〰, polyethylene oxide, 〰CH 2 OĊHCH 2 O〰. Radicals from polypropylene oxide, dextran, dextrin, soluble starch, and the disaccharide maltose were unidentified; the last three were strikingly similar. Products of secondary C-C scission were not observed with certainty. It is presumed that such reactions are slow compared to the time-scale of the experiment, 10 msec. However, some evidence exists for a very rapid β -OH loss in carbohydrate radicals and a slow C-O scission in polyethylene oxide radicals. A large number of related small molecule radicals were investigated, and hyperfine splittings and g -values are reported.

Both pentafluorobromobenzene and pentafluoroiodobenzene are reactive intermediates and can be used to introduce the perfluorophenyl (C 6 F 5 -) group into a variety of new compounds. The chief methods used are the Grignard coupling or addition reaction as well as the Ullmann condensation reaction. Some of the new compounds prepared were pentafluorobenzonitrile, perfluorodiphenyl, pentafluorophenyl- α -ethanol, and pentafluorostyrene.

Mixtures of hexafluorobenzene and benzene were irradiated in liquid phase by means of a Co 60 gamma source at 20° and at 218° C. Perfluoroheptane and various binary mixtures involving perfluoroheptane, hexafluorobenzene, benzene, and cyclohexane were also irradiated at 20° C. Hexafluorobenzene resembled benzene very closely in its behavior upon radiolysis. Generally the fluorocarbon-hydrocarbon mixtures evolved much more SiF 4 (indicating the formation of HF, which reacts with the glass vessel) than the pure fluorocarbon components. The polymer from hexafluorobenzene-benzene mixtures was probably rich in cyclohexadiene and cyclohexene units, resembling that from pure benzene, and its composition ratio exhibited a strong "alternating" tendency. The results are discussed in terms of free-radical and excited-state mechanisms. At 218° C hexafluorobenzene and also its mixtures with benzene showed qualitative differences from their behavior at 20° C, although the G values for SiF 4 and polymer remained moderate.

The rate of decomposition of polytetrafluoroethylene, exposed to gamma radiation in a flowing helium atmosphere, was studied in the range of temperatures 330 to 450 °C, dose rates 0.1 to 7.6 MR/h, and sample thicknesses 0.0006 to 0.01 cm. Rate measurements were made with a thermal conductivity cell in the exit stream, which recorded essentially the difference between the thermal and radiation-induced rate, in total molecules of volatiles per second. At temperatures below about 400 °C, the volatile products were a complex mixture. Above 400 °C, tetrafluoroethylene was the major product, and the radiation-induced rate had an activation energy* of 70 to 84 kJ/mol. The radiation-induced rate is proportional to square root of dose rate, after appropriate allowance for the thermal initiation is made. Analysis of the results suggests that the rate of the thermal initiation has a very high preexponential factor, 10 28 to 10 30 s- 1 . The activation energy for termination is large, E 4 > 155 kJ/mol. Diffusion and reverse reaction appear to be minor factors above 400 °C, but a surface reaction may be important. The thermal decomposition mechanism seems clearly to consist of random initiation, termination by bimolecular recombination and a short kinetic chain (13 at 480 °C).

Nucleophilic reactions of hexafluorobenzene and related polyfluorobenzenes were studied in detail. Reaction of hexafluorobenzene with hydroxides, alcoholates, aqueous amines, and organolithium compounds led to the substitution of one or more fluorine atoms. The structures of the products were determined, using near infrared and nuclear magnetic resonance spectra. Fluorine is replaced more readily than chlorine, bromine, iodine, or other groups. In the majority of the products in which two of the fluorines in hexafluorobenzene were replaced, the substituting groups were para to each other. However, depending on the reagents other orientation effects were noted. The reaction mechanisms were a function of reagents and conditions. The most prevalent mechanism is presumably the displacement of a fluoride anion by another anion, probably via the formation of transition complexes of different lifetimes. However, simple ionization or attack by neutral species may occur under some conditions. The diazotization and oxidation of pentafluoroaniline were also investigated.

As part of a study of vulcanization, propylene as a model compound for natural rubber has been reacted with sulfur alone, with hydrogen sulfide alone, and with each of these materials in the presence of certain accelerators. Butadiene as a model compound for intermediate conjugated systems found in vulcanized rubber by means of infrared studies has been similarly studied. Results of mass spectrometer analyses of the volatile portions of the reaction products indicate the formation of sulfides, disulfides, and carbon-to-carbon bonds. Zinc dimethyl dithiocarbamate (ZnDMDC), a vulcanization accelerator, facilitates the formation of hydrogen sulfide from the olefin or diolefin in the presence of sulfur, and in turn promotes the reaction of hydrogen sulfide with the olefin and diolefin. The ZnDMDC-accelerated reaction of hydrogen sulfide and sulfur with the diolefin may account for the reduced conjugation observed in vulcanizates accelerated with ZnDMDC. Studies with free radical accelerators show that a mechanism other than a free radical chain mechanism is involved in the formation of diisopropyl sulfide in the reaction of propylene with sulfur (or hydrogen sulfide) and certain substances that facilitate the reactions. The same conclusion applies to the formation of a nonvolatile residue in the ZnDMDC-accelerated reaction between propylene and sulfur. Other phases of the reactions involve the formation of compounds from what appear to be free radical fragments of the original molecule. In most of the reactions, appreciable portions of the reaction products are nonvolatile.

Theoretical equations are developed for typical decompositions of polymers including those in which the volatilization does not follow a simple "reaction order" and those made up of a composite of several reactions of differing energies of activation. The effects of order, activation energy, heating rate and temperature dependence upon the calculated thermograms is illustrated. The literature on thermogravimetric kinetics is critically reviewed and coalesced into a logical and coherent development stressing the interrelation of methods and employing a consistent system of notation. As a result, a number of improved methods and new methods for the analysis of kinetic data applicable to the complex systems mentioned above are developed. It is concluded that methods involving a variable rate of heating or involving several thermogravimetric traces at different rates of heating are capable of establishing the uniqueness of kinetic parameters. A new method of determining initial parameters from rate-conversion data is developed. A novel concept is employed of programming reaction variables (in this case, the heating rate) in a manner which greatly simplifies the mathematics of the kinetic system and which shows promise of a wide range of applicability in the area of rate processes.

The synthesis and polymerization of 2,3,5,6-tetrafluoro-4-trifluoromethylphenol (heptafluoro- p -cresol) is described. The polymer, poly- p -oxyperfluorobenzylene (polyperfluoro- p -benzylene oxide), is probably formed through the perfluoro- p -quinonemethide intermediate obtained by the intramolecular loss of either hydrogen fluoride or a metal fluoride. The polymer has a structure analogous to that reported for the polymer derived from p -trifluoromethylphenol under similar conditions. In the course of the synthesis of the monomer, heptafluoro- p -cresol, a novel synthetic method was discovered. The synthesis consists in the prior preparation of 1- t -butoxy-2,3,5,6-tetrafluoro-4-trifluoromethylbenzene and its subsequent thermal decomposition into the isobutylene and the desired cresol. Similarly, N-t -butyl-2,3,5,6-tetrafluoro-4-trifluoromethylaniline undergoes a similar liquid phase pyrolysis into isobutylene and 2,3,5,6-tetrafluoro-4-trirluoromethylaniline. However, during the course of this pyrolysis, practically all of the aniline undergoes polymerization with the concomitant loss of hydrogen fluoride. The polymer is formed by the same mechanism operative in the thermal polymerization of p -heptafluorocresol except that additional quantities of hydrogen fluoride can be eliminated from the - NHCF 2 - segments of the polymer chain thereby introducing - N = CF - units into the polymer backbone. Other t -butyl derivatives were synthesized and their thermal decomposition studied. Several possible mechanisms for the decomposition of these t -butyl compounds are considered.

Pyrolysis of tribromofluoromethane yields chiefly hexafluorobenzene. Copyrolysis of this material with several bromine-containing compounds was studied at 540 °C and under several atmospheres' pressure of nitrogen gas. The addition of bromine or dibromodifluoromethane has very little effect on the pyrolysis products of tribromofluoromethane. Copyrolysis with carbon tetrabromide or bromoform yields increased amounts of bromopentafluorobenzene and dibromotetrafluorobenzene at the expense of hexafluorobenzene. The addition of relatively small amounts of 1,1,1-tribromo-2,2,2-trifluoroethane gives a significant yield of octafluorotoluene.

Several fluorocarbon polymers were irradiated with Co 60 gamma radiation at doses up to 10 22 ev/g. The polymers studied included polytetrafluoroethylene, polytrifluoroethylene, polychlorotrifluoroethylene, a copolymer of tetrafluoroethylene with hexafluoropropylene, and several rubbery vinylidene fluoride copolymers. G -values were measured for volatile products, for free radicals detected by electron spin resonance, and, in the case of polychlorotrifluoroethylene, for scissions. The course of degradation or crosslinking was followed by zero-strength-time and tensile-strength measurements. It was found that for polytetrafluoroethylene and its hexafluoropropylene copolymer the presence of air-accelerated scission drastically. The mechanism of the radiation-induced changes is discussed in terms of free-radical intermediates.

Cross-linking predominates over chain scission during the irradiation of concentrated aqueous dextran solutions by cobalt-60 gamma rays in the absence of oxygen. An extensive and long-lived postirradiative viscosity decay, which has not been previously reported, is attributed to the agency of hydrogen peroxide formed during the radiolysis of water. Solid dextran primarily degrades upon γ -irradiation while dextran triacetate is borderline between dominant scission and cross-linking. Both exhibit a postirradiative viscosity decrease when irradiated in the presence of water vapor. Electron spin resonance spectra of dextran in the solid state and in aqueous solution are presented and compared. Spin resonance spectral and chemical evidence concerning the mechanism of cross-linking and postirradiative decay reactions is presented. There is conflicting evidence for the presence of oxyradicals. Speculations are made concerning possible mechanisms of oxyradical formation and their role in the production of ether and peroxy linkages.

The syntheses of perfluorophenyl ether and poly (perfluorophenylene ethers) are described. These materials were prepared by the reaction between potassium pentafluorophenoxide and hexafluorobenzene in different solvents with varying conditions of temperature and pressure. In dimethylformamide or tetrahydrofuran, potassium pentafluorophenoxide shows little tendency to react with hexafluorobenzene. In methanol, only exchange products such as pentafluoroanisole were observed. No polymers were obtained in these solvents. In water, the reactivity of pentafluorophenoxide salts was increased greatly, for reaction occurs readily with or without the presence of hexafluorobenzene. The reactions in aqueous systems are complex and give rise to a variety of products. From these reactions the following compounds were isolated and identified: perfluorophenyl ether, bis(pentafluorophenoxy)tetrafluorobenzene, 2,4,5,6-tetrafluororesorcinol, pentafluorophenoxytetrafluorophenol, and various polyperfluorophenylene ethers of varying chain lengths. Identification of the smaller molecules was made by chemical, mass spectrometer, infrared, and nuclear magnetic resonance analyses. Poly(perfluorophenylene ethers) were prepared having molecular weights of 1700, 4300, 6500, and 12,500. A crosslinked polyether of this type was also synthesized, which had rubbery characteristics above 90 °C.