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The effect of the aluminium cathode microstructure on zinc nucleation has been investigated through surface examination by SEM and cyclic voltammetry. Zinc nucleation is strongly affected by the surface preparation and impurities present in the aluminium. For chemically pure aluminium, the oxide film on the surface plays an important role during zinc nucleation and crystal growth. Thickening the barrier oxide film inhibits nucleation while a reverse effect can be obtained by thinning or removing the oxide film. In the case of a dilute aluminium with iron alloy, following anodization, the Al−Fe intermetallic phases provide conductive paths through the oxide film resulting in zinc nucleation.

The effect of fluoride ions on the corrosion of aluminium in sulphuric acid and zinc electrolyte has been investigated through thermodynamic analysis and corrosion experiments. The solution chemistry of aluminium, zinc, and iron in aqueous solution in the absence and in the presence of fluoride ions was studied with the construction of the Eh-pH diagrams for the Al−F−H2O, Zn−F−H2O and Fe−F−H2O systems at 25°C. In the presence of fluoride ions, aluminium can form a series of aluminium-fluoride complexes depending on the fluoride concentration and pH whereas zinc and iron can form soluble or insoluble metal-fluoride complex species only at relatively high fluoride concentration and at higher pH values. Experimental results show that in the presence of fluoride ions, the corrosion of pure aluminium in sulphuric acid is due to uniform dissolution and the reaction rate depends on the fluoride concentration. In zinc electrolyte containing fluoride ions, zinc deposits onto the pure aluminium substrate spontaneously and the amount of deposited zinc also depends on the fluoride concentration. On the other hand, the presence of iron in the Al−Fe alloy accelerates the corrosion of aluminium in H2SO4 and zinc electrolyte significantly and prevents the deposition of zinc on the aluminium surface. The effect of fluoride ions on zinc adherence to the aluminium is also discussed.

The preferred process for the production of cuprous oxide powder is via the anodic dissolution of copper in alkaline solution of sodium chloride. The principal reactions are as follows: $$\begin{gathered} Cu + nCl^ - = CuCl_n^{1 - n} (n = 2, 3) \hfill \\ 2H_2 O + 2e = H_2 \uparrow + 2OH^ - \hfill \\ 2CuCl_n^{1 - n} + 2OH^ - = Cu_2 O \downarrow + 2nCl^ - + H_2 O \hfill \\ \end{gathered} $$ In the present investigation the basic electrode processes were studied systematically under a broad range of conditions using linear sweep voltammetry. Variables studied include the concentration of sodium chloride and sodium hydroxide (i.e., alkalinity), temperature of the solution, two categories of additives (an inhibitor for preventing the deposition of spongy metallic copper powder on the cathodes, and a chemical reducing agent for reducing the cupric ions to the cuprous state), and the effect of carbonate ions (resulting from the spontaneous absorption of carbon dioxide from the air by sodium hydroxide). Useful guidelines concerning the electrolysis conditions, additives, and the concentration limit of carbonate ions have been established. The proper operating conditions can be considered to be as follows: 80–85°C, NaCl 240–260 gl−1, NaOH below 1 gl−1. Conditions pertaining to the use of additives are the following: calcium gluconate 0–5 gl−1, Na2CrO4 below 0.5 gl−1, Na2Cr2O7 below 0.25 gl−1, NH2OH·HCl below 2.5 gl−1, N2H4·H2O below 2.5 gl−1, sucrose 0–5 gl−1. Special attention must be given to eliminate or reduce the presence of carbonate ions in the electrolyte below 0.25 gl−1 Na2CO3.

Practical electrosynthesis of cuprous oxide powder was carried out on a laboratory scale in a cell specially constructed both with and without a diaphragm under the various operating conditions guided by the authors' previous research. The electrolysis was appraised in terms of the quality of the cuprous oxide product, the electrodissolution of the copper anode, and the SEM microstructure of the cuprous oxide powder. In a cell having a diaphragm, of which nylon fabric is the best, the optimal electrolysis operating conditions are: 250gl−1 NaCl, 0.1–1.0gl−1 NaOH, 500–1500Am−2, 80°C, perforated titanium sheet as the cathode, and around 3% cell volume of electrolyte circulation per minute. Under these conditions a product containing more than 97% cuprous oxide can easily be produced with very stable electrolysis and quite uniform dissolution of the copper anode. To eliminate the use of a diaphragm in the cell, the addition of sodium chromate, sodium dichromate, or calcium gluconate is effective in a sense, depending upon the requirements of the cuprous oxide product. For a product in which more than 95% cuprous oxide and no copper powder are required but a slightly higher content of chloride is allowable, sodium chromate and dichromate can be proposed for use with the former around 0.03–0.05gl−1 and the latter around 0.020–0.025gl−1, although the copper anode will not be perfectly evenly dissolved. For a product in which more than 97% cuprous oxide is demanded and a very small amount of copper powder is tolerated, calcium gluconate would be acceptable at around 4.5gl−1 with quite even dissolution of the copper anode. As to the auxiliary additives, hydrazine hydrate has a negative effect on the quality of the cuprous oxide product. Sucrose can cause a small increase in the chloride content but can make the particles of cuprous oxide more compact thereby increasing sharply its apparent density. Hydroxylamine hydrochloride is the best auxiliary additive which has a positive effect on the purity of the cuprous oxide product but produces no obvious change in the microstructure on the cuprous oxide particles. Even though most work has been concentrated on the electrolytic process, the subsequent processes are equally important: 65–70°C, distilled water for washing, benzotriazole in ethanol solution for stabilization of the cuprous oxide, and 100°C at a vacuum of less than 20mm Hg for drying seem to be satisfactory. A vacuum drying temperature of 55–60°C may be more appropriate to ensure against any oxidation of the product.

We examined the effects of three forms of host plant resistance in tomato, Lycopersicon esculentum, on the potato aphid, Macrosiphum euphorbiae. Mi-1.2, a resistance gene (R-gene) in tomato that deters aphid feeding, reduced the population growth of both potato aphid isolates tested, although it appeared to have a greater impact on isolate WU11 than on isolate WU12. The results suggest that there may be quantitative differences in virulence between these two aphid isolates. We also examined two distinct forms of acquired resistance in tomato, jasmonic acid (JA)-dependent and salicylic acid (SA)-dependent induced defenses. Exogenous foliar application of JA triggered expression of a JA-inducible proteinase inhibitor in tomato cultivars with and without Mi-1.2, although the effects of treatment on aphid performance differed between these cultivars. JA-treatment reduced aphid population growth on a susceptible tomato cultivar that lacks Mi-1.2, but did not significantly enhance or inhibit aphid control on a near-isogenic resistant tomato cultivar that carries this gene. Foliar application of an SA analog, benzothiadiazole (BTH), was used to induce SA-dependent defenses. BTH treatment reduced the population growth of both aphid isolates on a susceptible tomato cultivar, and also enhanced aphid control on a resistant cultivar. The results indicate that both SA- and JA-dependent acquired resistance in tomato have a direct negative effect on a phloem-feeding insect. Furthermore, this study demonstrates that acquired resistance and R-gene-mediated resistance can interact for enhanced suppression of insect herbivores.

This is the second update of a study of 3,444 taconite miners and millers who were first exposed to taconite, with associated exposures to silica and nonasbestiform amphiboles, in the period 1947 through 1958. Previous analyses of deaths through 1977, and again through 1983, showed no significant excess deaths from any specific causes. The present study continues the follow-up through 1988, adding 14,748 person-years of observation and 261 death certificates for analysis. The population, reduced to 3,431 because of the detection of 13 earlier duplications, has now been observed for 101,055 person-years, with 1,058 deaths and 1,039 death certificates. Death certificates were obtained for 98.2% of those known to be dead. The total number of deaths was significantly fewer than expected. Based on US rates, the standardized mortality ratio (SMR) was 83 (ie, 83% of expected). Based on Minnesota death rates, it was 91. With both US and Minnesota death rates, the SMRs for malignant neoplasms, cancer of the respiratory tract, cancer of the digestive system, heart disease, nonmalignant respiratory disease, and cirrhosis of the liver were all below 100. Slightly elevated SMRs were found for cancer of the colon, cancer of the kidney, and lymphopoietic cancer. These elevations were not statistically significant. Separate analyses were made of total deaths, lung cancer deaths, and kidney cancer deaths in men who had worked with taconite for time periods of less than 1 year, 1-5 years, 5-10 years, and over 10 years, during observation periods less than 10 years, 10-20 years, and over 20 years.(ABSTRACT TRUNCATED AT 250 WORDS)

It is shown that in a series of precipitated iron catalysts, some show a break in the Anderson-Schulz-Flory (ASF) plot of the distribution of linear products and others do not. It is also shown that the above break is due solely to the change in slope of the linear paraffins and that no such break occurs in the distributions of α or β-olefins. Our conclusion is that the paraffins and olefins are all primary products and that each has a characteristic rate of termination, but all have a common rate of propagation. A growth scheme which explains our observations is presented. On a constate que, dans un serie de catalyseurs au fer precipite, certains presentent une discontinuitye dans la representation graphique de la distribution d' Anderson, Schulz et Flory des produits lineaires, alors que d'autres n'en presentent pas. On a aussi note que cette discontinuee n'est due qu'au changement de pente des paraffines lineaires et qu'aucune discontinuitye de ce type ne se produit dans les distributions des α- ou des β-olefines. Notre conclusion est que les paraffines et les olefines sont toutes de produits primaires et que chacune a une vitesse caracteristique de terminaison, alors que toutes ont la meme vitesse de propagation. On presente un schema pour la croissance qui explique ces observations.

Methylcyclopentadienyl manganese tricarbonyl (MMT) is effective in raising the octane level of gasoline and is currently used in Canada for that purpose in a maximal concentration of 18 mg Mn/l (slightly less than 0.07 g Mn/U.S. gal). It has been estimated that if MMT were used in all U.S. gasoline in these amounts, the median increase of Mn in ambient air would be not more than 0.05 microgram Mn/m3, with increments generally less than 0.5 microgram Mn/m3 along urban corridors. The scientific literature was reviewed to determine how the increases in environmental manganese predicted from MMT use would relate to the amounts in the natural environment and necessary to life and to the concentrations associated with toxic effects. Even with additional manganese from the use of fuel additives, total Mn intakes would remain within the range of average amounts absorbed from food and water. Respirable manganese in ambient air due to MMT combustion would be many order of magnitude below the concentrations associated with occupational manganism and respiratory problems and also below those reported in isolated episodes of respiratory symptoms in communities near ferromanganese plants. Evidence was reviewed on the possibilities of: (1) increased absorption of inhaled manganese compared with ingested manganese; (2) hypersusceptibility of infants and persons of advanced age; and (3) increased absorption associated with iron deficiency. While relevant to high levels of exposure, these factors would not be expected to lead to toxic effects from the very low concentrations of Mn resulting from MMT use. Experimental animals that inhaled the combustion products of MMT in concentrations of approximately 10, 100, and 1000 micrograms Mn/m3 for 9 mo did not show toxic effects, although there was temporary elevation of tissue levels of Mn. Rhesus monkeys, susceptible to the neurologic effects of Mn, showed no symptoms after inhaling the combustion products of MMT in concentrations of 100 micrograms Mn/m3 for up to 66 wk. Monkeys exposed to 5000 microgram Mn/m3 also showed no symptoms. There is thus a wide margin of safety between the intakes of Mn essential to health and the high concentrations that have been associated with toxic effects. The small amounts of manganese added to the environment by the combustion of MMT used as a fuel additive would be comparable to the normal background and should not create health problems.

1. The relative effectiveness of a number of growth substances, both indole and naphthalene derivatives, in delaying leaf abscission in Coleus was tested by two methods of applying the compounds: by aqueous sprays and by lanolin mixtures applied by hand to cut petiole surfaces. 2. In the case of the spray applications the maximum effectiveness in delaying abscission was reached at approximately 0.05 per cent concentration of all compounds, with the exception of indoleacetic acid, which showed still greater effect at 0.1 per cent concentration. In most instances with the lanolin applications 0.05 per cent also represented the approximate maximum effective concentration. 3. The relative order of effectiveness of the various compounds differed considerably in the two methods of application. At the maximum effective concentration methyl indolebutyrate was the most effective in lanolin applications on petiole stubs, whereas in the spray application method β-naphthoxyacetic acid proved most effective. 4. With a...

Percival Allen, J. H. Gaddum, and S. C Pearce writing in Nature in 1945, all have emphasized the advantages of using the simple and powerful methods afforded by logarithmic transformations in analyzing nonnormal distributions, although it had been amply demonstrated in the relative growth of animal parts by (Huxley (1932)). We have undertaken to illustrate graphically the use of logarithm and power transformations for growth models of trees in orchards and tree organs. Various parameters based on literature, either age or size dependent, are described by power functions, log-log linear curves of the type y = bxk, or semi-log linear curves, exponential functions where y = aebx. Tree height or trunk diameter versus tree age, tree-leaf surface area or number on the tree versus tree age, leaf area versus length, or leaf area versus width are linear log-log functions. It is shown that the first pair of parameters are not normally distributed; latter pairs were demonstrated to be normal. Fruit yield was a nonlinear logarithmic function of tree age and their annual size-frequency distributions were not normal, except for infinitely large populations. Individual fruit size is a linear function of log fruit age, but only the log-log relations are linear for fruit dimensions (diameter, volume, and mass) versus packing number. Log branch fresh weight, leaf and fruit fresh weight are linear functions of log tree age, as are logs of branch dry weight, of branch diameter, of number of branches and surface areas and of volumes. High positive correlations between woody organ ages and dry organ densities invalidate the Rashevsky theoretical growth equation. Insertion of new density terms satisfy validity requirements. Frequency distribution of branch-diameter per tree is a linear log-log function. It is postulated that the linearity of the log-log and semi-log dimensional relationships in plant growth result from similar physical and chemical relationships underlying growth as outlined by kinetic theory.

The occurrence of several outbreaks of illness among workers handling castor bean pomace at eastern seaports in 1958 and 1959 led to an investigation of the toxicity of a number of commercial preparations. The conventional hemagglutination test and a toxic assay were used to study 14 commercial samples. The agglutination activity may be destroyed by heat without complete destruction of the toxic activity. Four of the samples collected were as toxic as the ricin sample used as the bioassay standard. In view of the potency of the toxin, ricin, and the failure of the agglutinating activity to correlate with the toxic properties of the samples, it is recommended that a toxin assay such as described in this paper be used to evaluate commercial preparations.

Comparisons were made of the composition of ‘Valencia’ oranges, Citrus sinensis Osbeck, from orchards in 6 major climatic zones used for citrus culture in the U. S. Six orchards, selected in a compact area in each location, were measured and sampled at intervals during 2 crop seasons. The locations were: Orlando, Fla.; Weslaco, Tex.; Tempe, Ariz.; Indio, Calif.; Riverside, Calif.; Santa Paula, Calif. Statistical evaluations showed that the seasonal trends for most measurements differed significantly among locations. Observations on flowering showed that full-bloom occurred from 1 to 2 months later in the Far-Western locations than in Texas and Florida. The extremes of the interval between an thesis and the beginning of ripening (a 9 to 1 ratio of total soluble solids to acid in juice) varied from 71/2 to 81/2 months in Weslaco, to 14 to 15 months in Santa Paula, but earliness or lateness of maturity could not be relatd in any simple, obvious manner to the characteristic of the seasonal temperature regimes in the 6 locations. In general, rinds were thinner, smoother and slower to color, and fruits larger, and juicier in Orlando and Weslaco than in the Far-Western locations. Total soluble solids and ascorbic acid in juice at comparable stages of maturity were not influenced in a predictable manner by location, although significant differences occurred in a given season. Of the juice constituents, the acids appear to be the most consistently influenced by climatic conditions during the rapid growth and maturation periods of fruit development. The warmer the climate, the more rapid was the rate of decrease of total acid concentration. Seediness of fruit was influenced by both location and season. Measurements of comparable samples of fruit obtained from widely divergent climatic parameters suggest that the numerous growth and metabolic processes involved in ripening of citrus fruits have independent internal controlling mechanisms. Apparently these processes interact in different ways with external environmental factors, and are not dominated by a pervasive, common internal maturity factor.

Four abscission materials were evaluated to determine their effects on ethylene production and abscission of fruit and leaves of orange (Citrus sinensis (L.) Osbeck cvs. Hamlin and Valencia): 5-chloro-3-methyl-4-nitro-1H-pyrazole (Release) glyoxal dioxime (Pik-Off), cycloheximide (3-[2-(3,5-dimethyl-2-oxocyclohexyl-2-hydroxyethyl]-glutarimide or Acti-Aid) and cycloheximide in combination with chlorothalonil (DS-27914). All chemicals enhanced internal fruit ethylene levels and subsequent fruit loosening. However, the magnitude and timing of the fruit ethylene response varied with each chemical and correlated with fruit loosening and subsequent retightening. The pattern of ethylene production may indicate the optimum fruit harvest period and the degree of leaf abscission for each chemical.

‘Redblush’ grapefruit seedlings, with and without leaves, were sprayed 1 to 5 times with 100 to 1000 ppm abscisic acid or 500 to 3000 ppm cycocel. Plants were subsequently exposed to several day/night temperature regimes which included 70°/50°, 90°/70°, and 95°/95°F. Both abscisic acid and cycocel delayed bud growth of leafy and defoliated seedlings. Abscisic acid was more effective than cycocel, and both compounds were most effective in delaying bud growth at lower temperatures, higher concentrations, and with more than one application. Abscisic acid was more toxic than cycocel, and both compounds were more toxic to defoliated plants than to leafy plants. Gibberellic acid overcame a correlative bud inhibition by the leaves, and abscisic acid decreased the effect of gibberellic acid.

Chest roentgenograms of 240 perlite workers employed for 1 to 23 years in the industry, showed no evidence of pneumoconiosis associated with perlite exposures. One individual, found to have simple pneumoconiosis, and one found to have complicated pneumoconiosis, had formerly been diatomaceous earth workers. Since only 28 of the men had been in the industry over 15 years and only seven for 20 years or more, continued surveillance is essential to make sure that there are no effects with more prolonged exposures. Studies of pulmonary function of the individuals who have had relatively long exposures are needed to supplement radiographic evidence.

This report is based on an analysis of deaths in 4519 battery plant workers and 2300 lead production or smelter workers during the years 1947 to 1980. Causes were coded to the seventh (1955) revision of the International Classification of Diseases. There were significant excess deaths for "other hypertensive disease" (444-447) and "chronic nephritis" (592-594) in both cohorts, the standardized mortality ratios (SMRs) being 320 and 475, respectively, for the former causes and 222 and 265 for the latter. Proportionate mortality analysis, which adjusted for race, also showed elevated ratios, 241 and 388 for the former causes and 296 and 186 for the latter. Deaths from other hypertension-related diseases did not show comparable excesses. Renal cancer deaths were fewer than expected, SMRs being 41 and 74, respectively.

The effect of protein insufficiency on immune responsiveness was investigated in inbred mice fed isocaloric diets low and normal in protein. Mice were tested for aberrations of cell-mediated and humoral immunities. Protein insufficiency enhances cell-mediated immunity while depressing or not affecting humoral immunity. Cell-mediated immunity was enhanced in testing: allogeneic skin graft rejection, spleen cell responsiveness to phytohemagglutinin, the graft-vs-host reaction, macrophage function, and resistance to viral and bacterial infections.

A review of chest films from 152 workers who had been employed five or more years in perlite mining or processing showed none with small opacities of profusion 1/0 or higher. There were 14 films with doubtful changes (0/1), but these showed no correlation with type or duration of employment. Pulmonary function was measured in 122 current employees from the same plants. Multiple regression analysis showed no significant association between years of employment in perlite and either forced vital capacity (FVC) or forced expiratory volume (FEV1). There was a significant association between pack-years of cigarettes and both measurements. In 66 workers tested in 1975 and again in 1983, there was an average annual decrease in FVC of 32 mL, with 26 mL predicted by the Knudson formula, which is based on nonsmokers. The average annual decrease in FEV1 was 24 mL with 26 mL predicted. Comparison of groups with differing smoking patterns showed that the decreases in both FVC and FEV1 were associated with smoking. The 28 men who had added four or more pack-years in the interval between tests showed decreases in FVC and FEV1 of 44 mL/year and 31 mL/year, respectively, with 26 mL/year predicted for both groups. Those with less than four added pack-years (which included 26 nonsmokers) had decreases in FVC and FEV1 of 23 mL/year and 19 mL/year with 26 mL/year and 27 mL/year predicted.

Several experiments conducted by our group over a period of 6 years have shown that nutritional stress, especially protein and/or calorie deprivation, leads to many, often dramatic, changes in the immune responses of mice, rats, and guinea pigs. Chronic protein deprivation (CPD) has been shown to create an enhancing effect on the cell-mediated immune responses of these animals. Humoral responses under CPD conditions were most often found to be depressed, but sometimes were unaffected, depending on the nature of the antigen employed. Chronic protein deprivation, consistent with the pattern just mentioned, improved tumor immunity by depressing production of B-cell blocking factors, and, in at least one instance, resistance to development of mammary adenocarcinoma in C3H mice was associated with evidence of increased numbers of T suppressor cells. Profound nutritional deficits (less than 5% protein per total daily food intake) depressed both cellular and humoral immunity. Early, though temporary, protein deprivation caused a long-term depression of both cellular and humoral immunity also, with the humoral component being the first to recover. Manipulation of protein and calories was found to have a profound effect on certain autoimmune conditions. Diets high in fat and low in protein favored reproduction but shortened the life of NZB mice, whereas diets high in protein and low in fat inhibited development of autoimmunity and prolonged life. Chronic moderate protein restriction permitted NZB mice to maintain their normally waning immunologic functions much longer than mice fed a normal protein intake. Further, the low-protein diet was associated with a delay in development of manifestations of autoimmunity. Decreasing dietary calories by a reduction of fats, carbohydrates, and proteins more than doubled the average life span of (NZB X NZW)F1 mice, a strain prone to early death from autoimmune disease. Histopathologic studies using immunofluorescent microscopy revealed that the development of the renal lesions caused by the deposition of antigen-antibody complexes, which is so characteristic of these mice, was markedly delayed.

A population of 10,173 men, employed in 37 plants, was identified as having worked for at least one year in jobs involving probable exposure to vinyl chloride monomer (VCM) prior to January 1, 1973. Of the 9677 men whose vital status was determined, 707 were known to have died. For 699, death certificates were obtained. The standardized mortality ratio (SMR) for all causes was 89, that for all malignancies was 104. The only type of malignancy found in significant excess was in the category of malignant neoplasms of the brain and other parts of the nervous system; 12 deaths occurred where 5.9 were expected, for an adjusted SMR of 203. There were slight but inconclusive upward trends in all malignancies, and for malignancies of the respiratory tract, digestive tract, and central nervous system associated with reported levels of maximum exposure to VCM. When groups in whom less than 20 years had elapsed from the first exposure were compared with those with 20 or more elapsed years, and 25 or more elapsed years, no significantly different SMR's were detected for major primary sites of malignancy. Plans for an updated study of mortality, to include deaths in the period 1973-1979 are briefly discussed.

Comparison is made between the saps of Valonia ventricosa of Florida and the Bermuda Halicystis, formerly known as V. ventricosa. An even higher percentage of potassium is found in V. ventricosa than in V. macrophysa, while Halicystis has been shown to have very little.