Showing papers in "Journal of The Society of Dyers and Colourists in 1956"

The morphology of boar spermatozoa.

Abstract: SYNOPSIS The morphological features of boar spermatozoa in freshly ejaculated semen and in semen exposed to various experimental treatments have been studied in stained smears and with the phase-contrast microscope and the electron-microscope. The spermatozoon of the boar closely resembles that of other domestic ungulates. The head is approximately 8.5μ long; it is twice as long as it is wide. The mid-piece is approximately 10μ long and the main tail-piece is 30μ long. The head is covered anteriorly by a cap-like structure—the acrosome. Evidence is presented to show that the acrosome has two components: the outer acrosome is the larger, the smaller inner acrosome is a crescentic structure. The segment-shaped area of overlap between the two parts of the acrosome forms the equatorial segment which is a feature of living boar spermatozoa. The surface of the head behind the acrosome impregnates with silver; this argentophil area is the post-nuclear cap. Three neck granules can be distinguished at the posterior border of the head and these are apparently connected to three bundles of neck fibres which the head receives from the mid-piece. The structure of the spermatozoon is altered by post-mortem changes; the most prominent changes occur in the acrosome. Evidence is presented that the post-nuclear cap is absent from dead spermatozoa. The development of the boar acrosome has been studied in sections stained by the PAS method and in unfixed tissues with the phase-contrast microscope. The development of the post-nuclear cap has been studied in sections impregnated with silver. The morphological features of epididymal spermatozoa have been studied in spermatozoa from different levels of the epididymis. The development of the acrosome is shown to resemble its development in the bull. Two separate components of the acrosome of the spermatid are distinguished. It is suggested that these develop into the two components of the acrosome of the mature spermatozoon. Migration of the cytoplasmic droplet from the neck to the mid-piece occurs at varying levels in the epididymis, but it is shown that it may occur in the head of the epididymis. The findings are discussed in relation to current ideas about the structure of mammalian spermatozoa.

The Photochemical Oxidation of Wool in the presence of Fluorescent Compounds

Abstract: A study has been made of the action of sunlight on wool treated with fluorescent brightening agents. The discoloration which occurs is due to oxidation of the wool and appears to be independent of the fluorescent agent used. There is considerable evidence to show that oxidation of the amino acid tryptophan is the main colour-producing reaction.

The Spectral Regions of Daylight which cause Fading

Abstract: Organic colouring matters are faded by absorbed ultraviolet and visible radiation up to a critical wavelength, above which radiation is non-actinic even if strongly absorbed. This wavelength is generally related to the normal light fastness of the colouring matter, “normal” referring to the substrate for which it was originally developed, e.g. vat dyes on cotton, disperse dyes on acetate rayon. The critical wavelength decreases as the resistance to fading increases, being in the red when the light fastness is 1–2 (minimum) and in the blue when it is 6–8 (maximum); there are, however, some exceptions to this rule. As long-wave radiations preponderate in daylight and as the absorption bands are usually strongest in the visible spectrum, fugitive organic colouring matters are mainly faded by visible light, whilst those of high normal light fastness can in general be faded only by ultraviolet, violet, and blue light. The differences between the composition of actinic radiation constituting daylight and that emitted by the enclosed carbon arc have been shown to be relatively unimportant as a possible source of gross anomalies in light fastness testing based on comparison with light fastness standards. These differences do, however, render meaningless any attempts to equate one hour's lamp exposure with so many hours' sunshine.

A Study of the Photochemistry of Dyes on Proteins and other Substrates

Abstract: The rates of oxidation and of reduction in aqueous solution, and of fading in films of a typical protein (gelatin) and a typical non-protein (methylethylcellulose), have been determined for several series of dyes of different chemical classes. The general conclusion reached is that the photodegradation of a dye may follow either of the alternative mechanisms of oxidation or reduction, but normally oxidation occurs more readily on all non-proteins and reduction on proteins. In photochemical oxidation of dyes on non-proteins the substrate does not necessarily take part directly, but in reduction on proteins some constituent of the protein itself appears to act as the reducing agent. The histidine side-chains are probably the active constituent. The conclusions in some instances have been confirmed by examination of spectral absorption curves of oxidation, reduction, and fading products of certain dyes.

An examination of the scales and bristles of Mallomonas in the electron microscope using carbon replicas.

Abstract: SYNOPSIS The species of the genus Mallomonas, classed amongst the algae, are small cells covered with characteristic silica scales and bristles. These are of considerable importance in the classification of the species, but only the coarser details are visible under the optical microscope. A direct electron microscope study yields much information about the fine markings on the scales, but the use of carbon replicas produces clearer, more easily interpreted micrographs, and permits the examination of the exterior of a complete organism. The scales and bristles of nine species, three of which are new, are described, and some variations in the markings within a single species are illustrated.

The Disperse Dyes — Their Development and Application

Abstract: The disperse dyes have come to be applied to a very large number and variety of fibres and have therefore achieved an importance which is probably greater than the weights used would suggest. They were the first type to be applied directly to a fibre from an insoluble suspension. Their preparation includes a process of particle size reduction and often subsequent drying, both in the presence of a dispersing agent. The mechanism of dyeing with them would seem to entail their passing from suspension through solution on to the fibre, to which they become attached by non-polar forces. The colouring matters used in the preparation of disperse dyes belong mainly to three chemical groups. The connection between dyeing and fastness properties on the one hand and chemical constitution on the other is in general indefinite. However, the best fastnesses are obtained by moving in the direction of greater molecular complexity, but this unfortunately is accompanied by a reduction in dyeing power. The introduction in recent years of the man-made fibres has accelerated the development of new application methods, and these are assisting the dyer to utilise these more complex dyes. This tendency emphasises that the achievement of better fastness with disperse dyes will require, as with other dyeing classes, a close understanding between, and the combined efforts of, both those working on the elaboration of new dye structures and those whose interests lie in one or other aspects of dye application.

The acrosome and post-nuclear cap of bull spermatozoa.

Abstract: SYNOPSIS A description is given of the development of the acrosome and post-nuclear cap of normal bull spermatozoa and of the abnormal “knobbed” spermatozoa of certain sterile bulls. The acrosome of the normal spermatid has two components—the “cap” and the “bead.” Evidence is presented that the acrosome of the mature spermatozoon has also two components—a PAS-positive, silver-negative component which is formed from the cap of the spermatid and a silver-positive component which is formed from the bead. It is suggested that the equatorial segment is a gap between the silver-positive component of the acrosome and the silver-positive post-nuclear cap. In “knobbed” spermatozoa the bead persists, the silver-positive component of the acrosome is not formed and no equatorial segment is detectable. The development of the post-nuclear cap of “knobbed” spermatozoa is normal.

Applications of an epoxide embedding medium to electron microscopy

Abstract: SYNOPSIS The Araldite embedding resin, described by Glauert et al., for preparing thin sections for electron microscopy has been tried on a wide range of materials and found to prevent completely the “explosion damage” so common with methacrylate polymers.

The Dyeing of Cellulose Acetate with Non‐ionic Dyes IIIndashDyeing from the Vapour Phase

Abstract: A study has been made of the absorption from the vapour phase, by secondary cellulose acetate, of five model dyes. These are p-nitroaniline, NN-dimethyl-p-nitroaniline, azobenzene, p-aminoazobenzene, and NN′-dimethyl-p-aminoazobenzene. The amounts absorbed at equilibrium have been measured, and their dependence on the vapour pressure of the dyes and the temperature of the substrate has been established. The vapour pressures of the dyes have been measured over a range of temperatures, those of azobenzene by manometry and the remainder by Knudsen's effusion method. The results together with the absorption data yield absorption isotherms from which are derived the isosteric heats of absorption of the dyes on cellulose acetate. The values, in the above order, are as followsndash21.2,–21.4,–17.8,–22.0, a22.7 kcal. /mole. The vapour pressure data are also used to evaluate the heats of vaporisation or sublimation of the dyes. These heats are applied to aqueous dyeing data already published to derive the absolute heats of association of the dyes on cellulose acetate. The results are in substantial agreement with the heats of absorption of the vaporised dyes. A brief study has been made of the absorption by, nylon and Terylene of vaporised azobenzene. The results for nylon yield a value for the heat of absorption of–18.0 kcal./mole. The results for Terylene are insufficiently complete for quantitative treatment.

Interaction between Chlorazol Sky Blue FF and Chrysophenine G in Aqueous Solution

Abstract: The absorption spectra of mixtures of Chlorazol Sky Blue FF and Chrysophenine G in aqueous solution have been measured at room temperature and at 60°c. Spectra of regenerated cellulose sheet dyed with the two dyes from mixture dyebaths have also been determined. Paper and column chromatography on mixtures of the two dyes confirm the formation of complexes, deduced from the spectral measurements. The heat of formation of the 1:1 complex of the two dyes, measured by direct calorimetry, is –15 kcal. per mole. Finally, equilibrium adsorption of the two dyes by cotton from mixture dyebaths has been determined. It is concluded that formation of a 1:1 complex occurs in aqueous solution to an appreciable extent even at 90°c. This complex formation explains in a semi-quantitative way the change in dye adsorption compared with that of the same dyes when applied singly. It is very probable that failure of dyeing data on single dyes to predict the behaviour of the same dyes in mixtures is due to interaction of this kind between the dyes in solution.

Electron microscope studies on diatoms.

Abstract: SYNOPSIS A review of the electron microscopy of diatom wall structure is given. The structure of the areolae and its variations are described. The diatoms are divided into nine groups based on their wall structure. The structures of the mucilage pores, spines and the raphe are described from the electron microscopic studies. As many as 80 genera and nearly 300 species have been investigated by different workers. A full list of these is given and the facts known about them analysed. The writer supports the view that structural details revealed by electron microscopy have a definite place in taxonomy.

The Dyeing of Acetate Rayon with Disperse Dyes VndashDiffusion Coefficients in Cellulose Acetate Film

Abstract: Values for diffusion coefficients, ranging from 0.05 to 4.8×10-10cm.2/sec., have been determined at 80°c, for disperse dyes in cellulose acetate film. The results indicate that the rate of dyeing of disperse dyes is mainly governed by the rate of diffusion in the fibre.

Influence of Temperature and Humidity on Fading

Abstract: Results are presented of experiments carried out in 1931 on the influence of temperature and humidity on the degree of fading of eighteen dyes on wool cloth.

The Importance of Temperature and Relative Humidity in Light Fastness Testing

Abstract: Differences in temperature during exposure are unlikely to be a direct cause of anomalous results in light fastness testing; differences in effective humidity, however, are of extreme importance and can cause variations of as much as four grades. The effective humidity during daylight exposure in Great Britain by the method specified in B.S. 1006: 1955 has an average value of 20%. Fading lamps should be operated at the same value: the effective humidity in certain lamps is too low and cannot be increased; in others it is too high when running under the makers' recommendations, but in such cases the preferred value can be easily obtained.

Disperse Dyes on Hydrophobic Fibres

Abstract: Although disperse dyeing appears at first sight to be very different from the application of dyes which are readily soluble in water, closer study shows that the two processes are in fact similar. But disperse dyes are not ionised, and dyeing does not depend on the presence of salt-forming groups in the fibre molecule, so disperse dyeing systems are much easier to treat theoretically than the older systems. In spite of the absence of ionising sulpho groups in the dye molecule, disperse dyes are not completely insoluble in water. They diffuse into the fibre from a very dilute aqueous solution, which, as dye is removed from solution by the fibre, is replenished owing to the presence of fine particles of suspended dye. At equilibrium a linear relationship is found between dye on the fibre and dye in the bath, so the dyeing process resembles the partition of a solute between two immiscible solvents.

Phase-contrast and electron microscope studies on the dictyosome and acroblast (Golgi bodies) in the male germ cells of the cricket.

Abstract: SYNOPSIS Electron micrographs of the dictyosomes and acroblasts of the male germ cells of the cricket reveal their ultramicroscopic structure to be comparable to that of the Golgi apparatus of vertebrates. They are made up of two components, namely, double membrane lamellae and vacuoles. These results suggest that the dictyosomes and acroblasts (Golgi material) are real cellular structures, distinct from mitochondria and homologous to the Golgi apparatus in vertebrate cells.

The Polarography of Azo Dyes

Abstract: Twenty-one water-soluble azo dyes– mono-, bis-, tris-, and tetrakis-azo, selected from the acid, basic, mordant, and direct dyeing classes–have been examined by polarographic methods. The object was to determine how far these methods could be used for the identification and estimation of azo dyes in general. With a few exceptions, the half-wave potential corresponding to the reduction of azo groups does not change very greatly from one dye to another, and this quantity has therefore little value as a general means of identification. When the correct experimental conditions have been established, the polarographic method lends itself to the accurate estimation of all the dyes that have been studied.

In the Footsteps of Perkin

Abstract: It is less easy to make Perkin's Mauve than may be supposed. With little more than the original patent specification as a guide, yet with all the facilities of modern laboratories, chemists of 1956 have experienced difficulty in preparing on a small scale Mauve equal in quality to that which Perkin & Sons manufactured almost a century ago.

II–The Effect of Liquor Ratio on Direct Dyeing

Abstract: Package dyeing has been carried out on a laboratory apparatus with a number of dyes, each in 6 and 20 volumes, with enough sodium chloride added at the commencement of dyeing to give roughly the same final exhaustion at the two liquor ratios for any particular dye. After 30 min., with the same rate of flow, the 6-vol. dyeing was always more level than the corresponding 20-vol. dyeing. Special consideration is given to a class C dye which without added salt has a very high exhaustion in low volumes, due to the salt contained in the dye. Here also the 6-vol. dyeing was more level than the 20-vol. dyeing after 30 min., although the former package was more than twice as heavily dyed. These observations have been confirmed by dyeing commercial viscose rayon cakes on a laboratory cake-dyeing machine with single dyes and mixtures. The advantage gained by working in low volumes is shown to be due to an increase in the dyebath cycle rate, and an expression is given showing the relationship of this to yarn weight and rate of flow. The variation in yarn weight in bulk cake-dyeing is considered in so far as it affects liquor ratio and dyebath cycle rate. In the second part of the paper the results are examined in the light of a theoretical model of package dyeing previously described. It is found that, when certain parameters are chosen to give a fit with measured skein-dyeing curves, the main conclusions about package dyeing based on the experimental results are substantiated by the model. At the same time, more information is provided on the rate of exchange of dyes between liquor and yarn within the package, and on the influence of the three basic parameters on which package-dyeing behaviour depends.

The Rates of Desorption of Level‐dyeing Acid Dyes from Wool

Abstract: A study of the initial rates of desorption of level-dyeing acid dyes from wool into sodium borate (borax) solution has indicated a linear relationship between the dye removed, expressed as a percentage of the total dye initially present, and the square root of the time. Activation energies of diffusion during desorption from wool have been determined for several dyes. The effects of method of application of dye, nature of dye, and nature of substrate on rates of desorption of acid dyes from wool have been determined. It is shown that the rate of desorption is controlled by the relative magnitudes of the forces of repulsion between the charged fibre and the dye anion and the forces of attraction, such as van der Waals, hydrogen bonds, etc., between fibre and dye. Any fibre modifieation which results in an increase in the number of free acidic groups, such as dyeing at low pH values, acid chlorination. or peroxide bleaching, increases the rate of removal of dye by alkaline solution.

On a possible explanation of the sudden dousing of the light by the new zealand glow-worm (arachnocampa luminosa)

Abstract: SYNOPSIS The New Zealand Glow-worm (Arachnocampa luminosa) is able suddenly to douse its light when alarmed. A suggestion is made as to how this could take place.

Modern Resin Finishing of Textiles Practice and Research

Abstract: The lecture surveys the development of the application of synthetic resins to textiles and the interrelation of practice and research. Resin application developed first on two main lines, viz. the use of emulsions of preformed vinyl-type polymers and the urea-formaldehyde crease-resist process. By using different preformed vinyl polymers a wide variety of finishes may be obtained, whereas the urea-formaldehyde finish, which is a key finish both practically and theoretically, is itself the basis of many finishes and has been the pattern for many other types of amino-formaldehyde resin finish. The importance of the location of the resin in or on the fibre is demonstrated in numerous systems. The use of resins for modifying handle, for imparting crease-resistance or dimensional stability, or for fixing embossed effects is now standard practice, but synthetic resins are finding increasing use in new outlets. Thus, phosphorus compounds are now being incorporated with the amino-formaldehyde type of resins to produce anti-flame finishes. Research is proceeding in the field of isocyanate chemistry, especially on polymer formation in and on textile fibres, and some progress is being made in practical application. A new class of polymeric substances– the silicones–has opened up a completely new field in the progress of water-repellency. It is shown that resin application to textiles is now a specialised study and that many more new developments may be expected.

The Influence of Histological Factors on the Attack of the Wool Fibre by Various Reagents

Abstract: An investigation, including optical and electron microscope studies, of the sequence of attack of various reagents on wool has revealed significant variations in the stability of the histological components of the fibre. In particular, further information has been obtained about the resistant membranes, together with additional evidence of a tubular resistant membrane lying immediately beneath the cuticular layer, and completely surrounding the cortex. This membrane is identified with the subcuticular membrane of Alexander and Earland1. The lability of the orthoeortex, and the greater stability of the paracortex, towards hydrolytic reagents, have also been confirmed. Observations on the action of oxidising agents, such as N-chlorourea and acid potassium permanganate, are also included. Details are given of a new rapid technique for obtaining fibre replicas for electron-microscopic examination.

Spectrophotometric Studies on Metal‐Dye Complexes I—The Reaction between Solochrome Violet RS (2‐Hydroxy‐5‐sulphophenylazo‐ β‐naphthol) and Tervalent Chromium

Abstract: An investigation has been made by spectrophotometric and chromatographic methods of the reaction between an oo′ -dihydroxyazo dye and tervalent chromium salts. The two complexes formed have been separated chromatographically and their spectra measured. Equilibrium constants for the interconversion of the two complexes have been determined, together with the heat, free energy, and entropy changes for this reaction.

The Dyeing of Orlon and Orlon Mixtures

Abstract: The physical characteristics of the acrylic fibre Orlon are described briefly Disperse dyes, basic dyes, acid dyes applied by the cuprous ion technique, and indigoid and thioindigoid vat dyes can be used to dye this fibre, and the dyeing and fastness properties of each class of dye are described fully The selection of dyes for specific purposes is discussed, and some advice on practical dyeing and finishing procedure included The dyeing of mixtures of Orlon with wool, nylon, and cellulosic fibres is described, and the paper concludes with some comments on the dyeing properties of analogous European acrylic fibres

A study of fresh mouse ascites tumour cells by ultra-violet, phase-contrast and interference microscopy.

Abstract: SYNOPSIS Various microscopical techniques have been used to study the morphology of ascites tumour cells. These methods have the advantage that they are applicable to fresh material, thus avoiding the artefacts usually caused by fixation and associated procedures. Certain observations concerning the distribution of nucleic acids and proteins within these cells are discussed.

On the relation between dictyosome and contractile vacuole in sponges

Abstract: SYNOPSIS 1. In the freshwater sponge Ephydatia, the osmiophile dictyosomes of the choanocytes are intimately related to the contractile vacuoles and show a great deal of morphological variation. In many cases the contractile vacuole itself possesses an osmiophile cortex. The condition here bears a general resemblance to the osmiophile vacuole-reservoir complex of some flagellates. 2. In the marine sponge Grantia, the osmiophile dictyosomes still show morphological variations. The vacuoles or chromophobe areas of the dictyosomes increase in size under the effect of hypotonic solutions. However, in ordinary or control material, the vacuoles show quantitative variations, though to a much lesser extent. 3. The inference to be drawn from the above-mentioned facts is that the sponge choanocyte dictyosome might be engaged in osmo-regulation. 4. From electron microscope work on the contractile vacuole cortices of protozoans, the parabasals of flagellates and the dictyosomes of Grantia choanocytes, it is quite clear that these structures have one thing in common, i.e. the presence in all of them of double lamellae or flattened closed vesicles, a character which they share with the metazoan Golgi apparatus.

Polarographic Investigation of Fur Dyes and their Oxidation Products

Abstract: The effect of pH on the oxidation of p-phenylenediamine has been investigated. It has been found that the maximum yield of one of the oxidation products– benzoquinone-1:4-bis-(2:5-diaminoanil). is obtained in a pH interval at which acidity has a marked effect on the state of aggregation of this compound. A change of pH from 6.0 to 7.3 causes its diffusion coefficient to change from 4.8 × 10-6 to 1.0 × 10-6 sq. cm./sec. As this pH interval covers that used in technical fur dyeing, even small fluctuations in pH have an intricate effect on the diffusion properties of this oxidation product, and therefore also on fur dyeing. Absorption spectroscopy indicates qualitative differences between oxidation products formed at different pH values. There is equivalence between the shifts of position and changes of shape of the absorption bands and the observed changes in slope of the curves of half-wave potential against pH for the different products. Catalase in the presence of hydrogen peroxide accelerates the oxidative condensation of benzoquinone-1:4-bis-(2:5-diaminoanil). This change can thus be effected very rapidly without applying the usual chromium or copper salts. Some applications of vertical paper electrophoresis are given, including separation and identification of oxidation products formed under different conditions, and also demonstration of differences between the dissociation constants of different nitro derivatives. Besides the use of the analytical results in determining the percentages of p-phenylenediamine and related compounds in batches from different suppliers, polarography provides a valuable means of determining exhaustion curves in dyebaths, usually comprising a mixture of five or six oxidisable, reducible, and non-reducible substances, where colorimetric methods would meet with difficulties. Hydrogen peroxide, which is always present, is eliminated by the addition of catalase to the different samples of dye liquor.