Showing papers by "The Hertz Corporation published in 1971"

Thermal Properties of the Starch/Water System Part I. Measurement of Heat of Gelatinisation by Differential Scanning Calorimetry

Abstract: The application of Differential Scanning Calorimetry to the gelatinisation of concentrated starch/water suspensions produced a well-defined endotherm under suitable conditions. Measurement of the peak area enabled the heat of gelatinisation to be calculated. The method has been applied to the following aspects of gelatinisation: — 1 Intercomparison of different starches, 2) Effect of granule size, 3 Application to wheat flour, 4 Effect of starch damage, 5 Staling of starch gels, 6 Amylose and amylopectin.

Effect on the Gelatinization Temperature of Wheat Starch Granules of Prolonged Treatment with Water at 50°C

Abstract: Undamaged wheat starch granules were treated in water at 50°C for 72 hours, and their properties then compared with those of the parent starch before and after gelatinization. Some of their attributes suggest that little alteration has occurred, but changes in others indicate that the internal structure of the granule has been modified, increasing its heterogeneity in some respects, but reducing it in others. In particular, gelatinization occurs at a higher but much more sharply defined temperature as compared with the range of temperatures shown by the mixture of untreated granules.

The effects of temperature on the composition and physical properties of the lipids of Pseudomonas fluorescens

Abstract: 1. Pseudomonas fluorescens was grown at various temperatures between 5°C and 33°C. The extractable lipids from organisms at various stages of growth and grown at different temperatures were examined. 2. The extractable lipids contained phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and an ornithine-containing lipid. The relative amounts of these lipids did not vary significantly during growth or with the changes in growth temperature. 3. The major fatty acids were hexadecanoic, hexadecenoic and octadecenoic acids and the cyclopropane acids methylene-hexadecanoic and methylene-octadecanoic acids. The relative amount of unsaturated acids (including cyclopropane acids) did not change significantly during growth, but increased with decreasing temperature. 4. Phosphatidylethanolamines with different degrees of unsaturation and containing different amounts of cyclopropane acids were isolated from organisms grown at 5°C and 22°C and their surface and phase behaviour in water was investigated. Thermodynamic parameters for fusion and monolayer results for cyclopropane and other fatty acids were examined. 5. The surface pressure–area isotherms of phosphatidylethanolamines containing different amounts of unsaturated fatty acids show small differences but the individual isotherms remain essentially unchanged over the temperature range 5–22°C. X-ray-diffraction methods show that the structures (lamellar+hexagonal) formed in water by phosphatidylethanolamine, isolated from organisms grown at 5°C and 22°C, are identical when compared at the respective growth temperatures. This points to a control mechanism of the physical state of the lipids that is sensitive to the operating temperature of the organism. 6. The molecular packing of cyclopropane acids is intermediate between that of the corresponding cis- and trans-monoenoic acids. However, substitution of a cyclopropane acid for a cis-unsaturated acid has insignificant effects on the molecular packing of phospholipids containing these acids.

Scanning Electron Microscopy of Wheat Starch. III. Granule Development in the Endosperm

Abstract: Study of A type starch granules from immature wheat endosperm with the scanning electron microscope has led to a developmental sequence being suggested. Evidence is provided which indicates that the initial minute spherical granule becomes a “nucleus” which is progressively surrounded in the equatorial plane by a continually enlarging structure which resembles two lips with a furrow between them. When the lips have completely surrounded the “nucleus” the thickness and diameter of the granule continue to increase in such a way that the furrow becomes shallower and is present in the mature biconvex structure only as a shallow score.

An analysis of the effects of nutrient supply on the growth of potato crops

Abstract: SUMMARY Fertilizer nitrogen did not delay tuber initiation by the potato variety King Edward in the field, but slowed the early growth of tubers. Later, N hastened tuber growth and the largest amounts prolonged it. Leaf and stem growth were increased by N from an early stage. Leaf area index (L) reached maxima of 2.5 to 3.0 with the largest amounts of N, and 1.0 with no nitrogen: L decreased after late July, faster with increased N, and only the largest amount prolonged the life of the haulm. N increased leaf area duration (D) by up to 125% in both years. D was 21% greater in 1964 than 1963, and net assimilation rate in August and September was larger; consequently mean yield was 50% more in 1964. Uptake of nitrogen and N % of dry matter were increased by increasing nitrogen. The N % of tuber dry weight remained constant or increased slightly from about 2 weeks after tuber formation, while N % of the leaves and stems decreased rapidly, and much N was transferred from tops to tubers. The 1964 results suggest that tuber growth depends on continued nitrogen uptake by the plant. P and K had small effects compared with those of N. K increased leaf area duration by 9% in 1963 and 3% in 1964, and yield by 11 and 8% respectively. P increased leaf area duration by 17% and yield by 9% in 1964. K had very small effects until the end of the season, when it prolonged the period of growth. P increased growth rates of all parts of the plant up to 4 weeks from emergence, and the differences in dry weight at that time persisted to maturity but did not increase.

How Does Rubber Slide

Abstract: Visual observations of contact areas between soft rubber sliders and hard tracks, and between hard sliders and soft rubber tracks, show that relative motion between the two frictional members is often only due to “waves of detachment” crossing the contact area at high speed from front to rear. Adhesion appears to be complete between these waves which are moving folds in the rubber surface, almost certainly produced by buckling. Buckling is attributed to tangential compressive stresses, predicted by a simple theory and qualitatively confirmed by experiment. The driving force for the waves of detachment is a tangential stress gradient, also theoretically predicted.

The site of action of pyrethrin i in the nervous system of the cockroach periplaneta americana

Abstract: Spontaneous nervous activity in the sixth abdominal ganglia of the cockroach is increased by much smaller concentrations of pyrethrin I than are needed to affect conduction in giant fibre axons, suggesting that the fatal lesions caused by pyrethrin I may be within the ganglia rather than associated with axonic conduction. Pyrethrin I is about 30 times more active than allethrin (Narahashi, 1962, a & b) against conduction in giant fibres. Zusammenfassung DER ANGRIFFSORT VON PYRETHRIN I IM NERVENSYSTEM DER KUCHENSCHABE PERIPLANETA AMERICANA Neurophysiologische Methoden wurden angewendet, um die Wirkung von Pyrethrin I auf die Leitung von Aktionspotentialen in Riesenfasern und den Umfang der Spontanaktivitat im 6. Abdominalganglion erwachsener mannlicher Kuchenschaben festzustellen. In Versuchen an isolierten Nervenpraparaten hatten Pyrethrin I-Konzentrationen von weniger als 10−7 M wenig Wirkung auf die Riesenfasern, wahrend so geringe Konzentrationen wie 10−10 M im Ganglion die Hohe der Aktivitat beeinflusten. Riesenfasern von Kuchenschaben, die vorher ortlich mit DL95s von Pyrethrin I behandelt worden waren, wurden 1–4 Stunden nach der Vergiftung stark beeinflust, wenn die Insekten stark angegriffen waren, doch war die Aktivitat im 6. Abdominalganglion zu diesem Zeitpunkt stark erhoht. Einige intraganglionare Neurone sind also gegenuber der Vergiftung mit Pyrethrinen wesentlich empfindlicher als die Riesenfasern, was darauf hindeutet, das die gefahrlichen Schadigungen durch Pyrethrine wahrscheinlich eher innerhalb der Ganglien als in peripheren Nerven auftreten. Die Wirkung von Pyrethrin I an Riesenfasern ahnelt den von Narahashi (1962 a + b) fur Allethrin beschriebenen, doch war Pyrethrin I etwa 30mal aktiver.

Amino acid composition and In Vitro digestibility of some protein fractions from three species of leaves of various ages

Abstract: Extracts from leaves of barley (Hordeum vulgare), lupin (Lupinus albus) and Chinese cabbage (Brassica chinensis) of different ages were fractionated. As the leaves age, chloroplasts are increasingly disrupted during extraction and the chlorophyll-containing protein becomes increasingly difficult to sediment. The amount of protein unassociated with chlorophyll varies with species, but not with leaf age. Analyses are given of selected chloroplastic fractions (sedimented and coagulated) and of the protein precipitated from the whole extracts and the various supernatant fluids. Amino acid composition of unfractionated protein is independent of species, except perhaps for methionine; leaf age has no affect on composition. The method of protein precipitation may influence the amount of lysine determined. Contrary to previous reports, chloroplastic and cytoplasmic protein do not have the same composition. Nutritional properties of the preparations are discussed in relation to their amino acid composition and to their known in vivo and in vitro behaviour. Comparison with the F.A.O. reference protein shows that sufficient lysine, both total and nutritionally ‘available’, is present in unfractionated and cytoplasmic protein, though it may be marginal in some chloroplastic fractions. The first limiting essential amino acid in all leaf protein preparations is methionine, and there is an adequate amount ‘available’ in cytoplasmic but not in unfractionated or chloroplastic protein. Reasons are suggested for the unavailability of methionine, and possibly cyst(e)ine, in the latter preparations.

Decomposition products of PVC for studies of fires

Abstract: Approximately seventy-five organic materials have been detected by gas chromatography in the thermal decomposition products of PVC and are shown by mass spectrometry and retention studies to consist mainly of aromatic and aliphatic hydrocarbons. Weight-loss experiments and time-resolved chromatography indicate that these products are formed mainly during dehydrochlorination. The products are modified by the presence of oxygen but no oxygenated organic species have been detected. Experiments to specifically monitor the production of phosgene from the decomposition of both a rigid PVC sheet and a PVC polymer in air are recorded. Phosgene has not been detected and direct seeding techniques have been used to investigate the detection limits of this material. PVC is known to release the toxic gases, carbon monoxide and hydrogen chloride, when involved in fires. It is shown that the minor products, including phosgene, make little or no contribution to the overall toxicity of the decomposition products.

The microbiology of moist barley storage in unsealed silos

Abstract: SUMMARY The microflora of moist barley grain and whole-crop barley silage stored in top-unloading, unsealed concrete-staved silos on six farms in England depended on the initial water content of the grain (23–58%), method of covering the grain, and the rate at which it was unloaded. Fungi and actinomycetes were fewest when the initial water content was more than 30%, and the grain was covered first with a layer of wilted grass, and then a plastic sheet. During unloading, the uppermost layer of grain remained in good condition provided 7.5 cm was removed daily. With an inefficient top-seal, the top grain heated and became mouldy, as it also did when unloading was slow. As the rate of unloading slowed, heating increased, and a characteristic succession of fungi and actinomycetes developed. With unloading at 7.5 cm/day or more, only yeasts, chiefly Endomycopsis chodatii Wickerham and Hansenula anomala (Hansen) H. & P. Sydow, were abundant, but at slightly slower rates of unloading Penicillium spp. also became common. Both these groups became less common as unloading was slowed further and were replaced, first by Absidia spp. and Mucor pusillus Lindt, then Aspergillus fumigatus Fres., Humicola lanuginosa (Griffon & Maublanc) Bunce, Micropolyspora faeni Cross, Maciver & Lacey, and Thermoactinomyces vulgaris Tsiklinsky as the heating increased. The number of spores (including bacterial cells) that could be removed from samples by blowing air ranged from 0.4–428 times 106/g dry weight of grain. Whole-crop barley silage contained 2.9–132 times 106spores/g dry weight. Similar species were isolated from whole-crop silage as from grain. Little moulding occurred deeper than 30 cm below surface of the grain. Concentrations of airborne spores were estimated periodically during two seasons. There were always more airborne spores than is usual in outdoor air. Without disturbance the silos contained 106-107 spores/m3 air, but when mouldy grain was unloaded concentrations increased to a maximum of 2860times106 spores/m3 air; more than half of these were bacteria and actinomycetes and a quarter Aspergillus flavus Link. Potentially pathogenic fungi and actinomycetes were frequent, particularly when they also occurred in the grain or capping materials for spontaneous heating. Some probably survived in dust deposits and were resuspended during unloading. Airborne spores were frequent around the silos when grain was unloaded and rolled. Workers should wear efficient dust respirators at these times and while inside silos.

Comparison of the bronchodilator and cardiovascular actions of salbutamol, isoprenaline and orciprenaline in guinea‐pigs and dogs

Abstract: 1. Bronchodilator and cardiovascular actions of salbutamol and isoprenaline have been compared in guinea-pigs and dogs. Orciprenaline was also included in some experiments.2. All three drugs antagonized acetylcholine-induced increases in pulmonary resistance. In addition they increased heart rate and decreased arterial blood pressure.3. Compared with isoprenaline, salbutamol has relatively stronger actions on bronchial and vascular beta-adrenoceptors than on cardiac beta-adrenoceptors, on which its action is very weak. In contrast, orciprenaline has similar potencies on beta-adrenoceptors in these three tissues.4. The positive chronotropic potency of intravenously or orally administered salbutamol was increased in conscious dogs. These heart rate responses to salbutamol were probably mainly reflex in origin.5. Salbutamol and orciprenaline were both longer acting than isoprenaline.6. The results support the idea of two distinct groups of beta-adrenoceptors. Salbutamol differentiates between bronchial and vascular beta(2)-adrenoceptors on the one hand and cardiac beta(1)-adrenoceptors on the other. Isoprenaline and orciprenaline do not differentiate between beta(1)- and beta(2)-adrenoceptors.

Phospholipids, liquids crystals and cell membranes

Abstract: 8 8 8 10 11 13 15 18 21 21 23 23 23 27 27 30 31 II. PHYSICAL STUDIES ON DRY PHOSPHOLIPIDS A. Introduction to polymorphism and thermotropic mesomorphism I. Polymorphism 2. Nomenclature of the polymorphic forms 3. Thermotropic mesomorphism 4. State of the hydrocarbon chains in mesomorphic phases B. Thermal analysis C. Infrared spectroscopy D. X-ray studies I. Single crystal 2. Powder studies on synthetic phospholipids (a) Phosphatidic acids (b) 1,2-diacylphosphatidylethanolamines ( cephaIins ) (c) 1,3-diacylphosphatidylethanolamines (cephalins) (d) 1,2-diacylphosphatidylcholines (lecithins) ( e) 1,2-diacylphosphatidylserines 3. Powder studies on natural phospholipids

Pepper veinal mottle virus-a new member of the potato virus Y group from peppers (Capsicum annuum L. and C. frutescens L.) in Ghana.

Abstract: SUMMARY Pepper veinal mottle virus (PVMV), a previously undescribed virus widespread in Capsicum annuum and C. frutescens in the Eastern Region of Ghana, is acquired and inoculated in 2 min feeding periods by aphids (Myzus persicae and Aphis gossypii); it is transmissible by inoculation of sap to eleven of fifteen Solanaceae and to five of forty-six other species within three of seventeen other families. The virus was propagated in Nicotiana clevelandii and Petunia hybrida, and assayed in Chenopodium quinoa, C. amaranticolor and C. murale. Sap from Capsicum annuum was infective after dilution to 10-3 but not 10-4, after 10 min at 55 but not 60oC, and after 7 but not 8 days at 25oC. Lyophilized sap from P. hybrida was infective after 6 years in vacuo. Yields of 10–25 mg of virus per kg of leaf tissue were consistently obtained from P. hybrida or N. clevelandii by extracting systemically infected leaves in 0.5 M borate (pH 7.8) containing 0.2% mercaptoethanol and chloroform, followed by repeated precipitation with 50 g polyethylene glycol (M.W. 6000) per l, several cycles of differential centrifugation and centrifugation in sucrose density-gradient columns. Virus preparations had ultraviolet absorption spectra typical of a nucleoprotein containing c. 6% nuclei acid (A 260/280 = 1.25; A 260/246 = 1.27) and contained numerous unaggregated and unbroken filamentous particles c. 770 times 12 nm which sedimented as a single component with a sedimentation coefficient (so20,w) of 155 S. PVMV contained RNA (moles %: G = 24, A = 23, C = 27, U = 26), and a single protein species with a molecular weight of 32000–33000 daltons. PVMV was not serologically related to potato virus Y (three strains), or to twelve other morphologically similar viruses, and seems to be a distinct member of the potato virus Y group. The cryptogram of PVMV is R/(I):*/(6):E/E:S/Ap.

Thermal-imaging camera tubes with pyroelectric targets

Abstract: Pyroelectric targets for thermal television can have broad spectral band-width, fast response to chopped signals and can operate uncooled. Analysis shows that targets of triglycine sulphate (TGS) are capable of good spatial resolution and high responsivity in practical thicknesses. The noise sources and constraints for electron beam readout in both cathode-potential and anode-potential stabilized modes are discussed, and favourable values of target resistivity and beam conductance have been measured. Predicted performance has been confirmed in demountable and sealed-off tubes working at standard television frame rates. The techniques described have also been used to make novel observations of the dynamics of domain growth in TGS.

Effect of aluminium on growth of tea (Camellia sinensis) and its uptake of potassium and phosphorus

Abstract: Tea seedlings were grown for up to 10 months in the glasshouse in an acid soil, to which solutions of varying K/Al concentration ratios were given weekly. During growth, the % K in the leaf dry matter increased with the labile K concentration but was not influenced by the Al concentration in the soil. However, the largest level of Al in soil decreased plant growth and % K in the dry matter increased linearly of Al in soil, plant height, number of leaves, dry matter and % K in the dry matter increased linearly with the K given to the soil. The % Al in the plant was not affected by the labile K and Al contents of the soil. A highly significant linear relationship was observed between Al and P uptake by parts of the plant and by the whole plant, even thought the soil was not treated with P as a basal nutrient. The Al/P ratios in the first mature leaf, total leaves and stems were 3·4, 3·0 and 0·8, respectively, after 6 months growth. Uptake mechanisms are proposed to explain this.