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At least 19 recordsLinked to original sources

PubMed2003

Characterization of inks and ink application for ink-jet printing: model and simulation.

Ink-jet printing quality is determined primarily by, among other factors, the printing engine and its inks. The printing engine controls the process of ink application and the scheme of ink mixing for th e generation of secondary and tertiary colors. The inks selectively absorb different wavelengths from the illumination and result in the visible color output. Therefore characterizations of the output print in terms of ink distribution and volume, the scheme of ink mixing, light absorption, and light scattering are of essential importance in controlling and understanding the quality of the color reproduction. I present a method to characterize the ink volume and the properties of the ink by means of spectral reflectance measurements and simulations. The simulations are based on the Kubelka-Munk theory, whose applicability to ink-jet printing is also discussed.

Journal Article↗

PubMed2004

Dopamine in the ink defence system of Sepia officinalis: biosynthesis, vesicular compartmentation in mature ink gland cells, nitric oxide (NO)/cGMP-induced depletion and fate in secreted ink.

The biosynthesis, localization and fate of catecholamines in the ink gland of the cuttlefish Sepia officinalis were investigated by combined biochemical and immunohistocytochemical methodologies. HPLC analysis of crude ink gland extracts indicated the presence of dopa (2.18+/-0.82 nmol/mg of protein) and DA (dopamine, 0.06+/-0.02 nmol/mg of protein), but no detectable noradrenaline or adrenaline. DA was shown to derive from L-tyrosine, according to experiments performed by incubating intact ink glands with [L-14C]tyrosine. The biosynthetic process involves a tyrosine hydroxylase and a dopa decarboxylase pathway and is independent of tyrosinase. The tyrosine hydroxylase activity was detected under conditions of tyrosinase suppression in the cytosolic fraction, but not in the melanosomal fraction, of ink gland extracts, and the presence of the enzyme was confirmed by Western-blot analysis. Dopa and DA were found to be released from the ink glands by processes controlled through the NMDA-nitric oxide-cGMP (where NMDA stands for N -methyl-D-aspartate) signalling pathway, as apparent from incubation experiments performed with [L-14C]tyrosine in the presence of NMDA, diethylamine NONOate (diethylamine diazeniumdiolate), a nitric oxide donor, 8-bromo-cGMP or a guanylyl cyclase inhibitor. Immunohistochemical results coupled with electron microscopy indicated that DA was concentrated in vesicles specifically localized in the mature melanin-producing cells of the ink gland proximal to the lumen and separated from the melanin-containing melanosomes. NMDA receptor stimulation or exposure to an NO donor caused a marked loss of DA immunoreactivity in mature cells, consistent with a release process. In the lumen of the ink gland, where mature exhausted cells pour their contents, DA immunoreactivity was found to be associated with the melanin granules, due apparently to physical adsorption. Overall, these results point to DA as a marker of cell maturation in Sepia ink gland subject to release by the NO/cGMP signalling pathway, and disclose apparently overlooked DA-melanin interactions in secreted ink of possible relevance to the defence mechanism.

Animals↗

PubMed1998

Defensive ink pigment processing and secretion in Aplysia californica: concentration and storage of phycoerythrobilin in the ink gland.

The marine snail Aplysia californica obtains its defensive ink exclusively from a diet of red seaweed. It stores the pigment (phycoerythrobilin, the red algal photosynthetic pigment, r-phycoerythrin, minus its protein) in muscular ink-release vesicles within the ink gland. Snails fed a diet of green seaweed or romaine lettuce do not secrete ink and their ink-release vesicles are largely devoid of ink. Successive activation of individual ink-release vesicles by ink motor neurons causes them to secrete approximately 55 % of their remaining ink (similar to the percentage of ink reserves released from the intact gland). The peripheral activation of vesicles appears to be cholinergic: 70 % of isolated vesicles were induced to squeeze ink from their valved end by solutions of acetylcholine at concentrations of 0.5 mmol l-1 or below. Ultrastructural analysis commonly found three cell types in the ink gland. The RER cells, the most numerous, were characterized by an extensive rough endoplasmic reticulum with greatly distended cisternae. This cell type is probably the site for synthesis of the high molecular mass protein of secreted ink. The granulate cells, less common than RER cells, had nuclear and cell areas significantly larger than those of RER cells. In addition, granulate cells of red-algal-fed snails had 4-14 vacuoles that contained electron-dense material with staining characteristics similar to that of ink in mature ink-release vesicles. The granulate cell's plasma membrane was regularly modified into grated areas, which both localized and expanded the surface area for coated vesicle formation and provided a sieve structure that prevented large particles in the hemolymph either from being taken up by, or from occluding, the coated vesicles. Electron-dense particles within coated vesicles were similar in size to those in granulate vacuoles but larger (on average by approximately 1 nm) than those that make up the ink. In green-seaweed-fed snails, granulate cells and their vacuoles were present but the vacuoles were empty. The third cell type, the vesicle cell, expands markedly, with its nucleus enlarging concurrent with cell growth until it is on average 50 times larger in cross-sectional area than the nuclei of either RER or granulate cells; the cytoplasm eventually becomes filled with ink, which obscures the mitochondria, vacuoles and nucleus. Continued cell expansion ceases with the appearance of an encircling layer of muscle and 1-3 layers of cells of unknown origin, thereby becoming the ink-release vesicle itself. The absorption spectra of the soluble contents of mature ink-release vesicles from snails fed red algae had peaks characteristic of the red algal pigment r-phycoerythrin or/and phycoerythrobilin. Immunogold localization of r-phycoerythrin showed no statistical difference in the amount of label within the ink-release vesicles, RER or granulate cell types. Furthermore, there was no localization of phycoerythrin immunoreactivity within the various cellular compartments of either the RER or granulate cells (nucleus, endoplasmic reticulum, mitochondria, vacuoles). Immunogold labeling in the ink gland ranged from 11 to 16 % of that for the digestive vacuoles of the rhodoplast digestive cells lining the tubules of the digestive gland. Our observations suggest (a) that the main form of the ink pigment in the gland is phycoerythrobilin or/and a non-antigenic form of phycoerythrin, and (b) that separation of the bilin from phycoerythrin (or its modification so that it is no longer antigenic) occurs before it reaches the ink gland, probably within the vacuoles of the rhodoplast digestive cells of the digestive gland. We propose the following model. The ink pigment, phycoerythrobilin, is cleaved from its protein in rhodoplast digestive vacuoles in the digestive gland. (ABSTRACT TRUNCATED)

Animals↗

PubMed1985

Emission of ink aerosol from ink-jet recorders.

As a follow-up of two patients found to be allergic to EKG*ink, a study was made, using spectrophotometric and light microscopic methods, of the factors influencing the emission of ink aerosol from ink-jet recorders used in electrocardiographs. Ink aerosol concentrations were only detectable by spectrophotometry under extreme conditions. However, the light microscopic method was sufficiently sensitive. At the slow paper speeds normally used (10-25 mm/sec) and under normal working conditions, the concentration of ink aerosol near the recorder was less than 0.1 microgram/m3; but aerosol emission increased exponentially with increasing ink pressure, i.e. increasing paper speed. At the highest paper speed studied (200 mm/sec), the aerosol concentration 36 cm from the ink nozzles was about 65 micrograms/m3. An increase in the distance from the ink nozzles to the chart paper resulted in a decrease in ink aerosol emissions. Aerosol dissipation was decreased by local exhaust ventilation of the ink-jet recorder. However, a protective shield designed to catch emitted ink aerosol only reduced the aerosol concentration at the measuring point at slow paper speeds. At higher paper speeds, the concentration increased. The average ink aerosol concentration near modern electrocardiographs is low, but some EKG operations may result in high peak concentrations. The formation of ink aerosol could be considerably reduced by changing the rheologic properties of the ink.

Aerosols↗

PubMed2001

Defensive inking in Aplysia spp: multiple episodes of ink secretion and the adaptive use of a limited chemical resource.

The seahare Aplysia spp. extracts many of its defensive chemicals from its red seaweed diet, including its purple ink, which is an effective deterrent against predators such as anemones and crabs. It is believed that the inking behavior is a high-threshold, all-or-none fixed act that nearly completely depletes the seahare of its ink supply. If a seahare depletes its gland of ink, it must seek out a source of red seaweed and then feed for at least 2 days to replenish its ink supply. This suggests that the animal would not be able to deploy ink more than once in rapid succession in response to successive attacks from one or more predators. However, we found that Aplysia spp. can secrete ink in response to three or more successive stimulations with (i) anemone tentacles, (ii) a mechanical stimulus, consisting of grabbing and lifting the animal from the substratum, or (iii) a noxious electric shock. A spectro-photometric measure of ink secretion showed that only approximately 48 % of the gland's releasable ink reserves are deployed initially. Thus, deployment of this defensive chemical is not strictly all-or-nothing, although the trigger mechanism is. Moreover, the animal tends to secrete a relatively fixed proportion (30--50 %) of its available ink reserves even after its gland has been depleted to approximately half its initial content. Since an animal need only use a proportion of its ink reserves to deter an attacker effectively, the inking behavior is adaptive in its economical use of a limited resource.

Animals↗

PubMed2002

Ballpoint pen inks: characterization by positive and negative ion-electrospray ionization mass spectrometry for the forensic examination of writing inks.

A method based on profiling of dye components by electrospray ionization mass spectrometry (ESI/MS) is described for the characterization of ballpoint pen inks. The method involves benzyl alcohol (30 microL) extraction of ink from paper. The extracts of ink lines 1 and 5 mm in length are used for direct ESI/MS analysis in positive and negative modes, respectively. The instrumental analysis takes 3 min. Basic and acid dyes in the inks are detected in the positive and negative modes, respectively, with each dye yielding one or two characteristic ion peaks. The mass spectrum, which is mainly a compositional signature of the dyes in the ink, was not affected by the type of paper from which the ink was extracted, or by natural ageing of the ink on document in the absence of light. However, exposure to fluorescent illumination caused dealkylation of polyalkylated basic dyes and resulted in changes in the homologous distribution of the dyes. In this study, a total of 44 blue inks, 23 black inks, and 10 red inks have been analyzed, and the mass spectra were used to establish a searchable library. ESI/MS analysis provides a simple and fast way to compare ink specimens and in combination with on-line library search permits rapid screening of inks for forensic document investigations.

Journal Article↗

PubMed2006

An evaluation of matching unknown writing inks with the United States International Ink Library.

Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.

Journal Article↗

PubMed2006

In a randomized study of envelope and ink color, colored ink was found to increase the response rate to a postal questionnaire.

OBJECTIVE: To assess the effect of the colors of the envelope and ink on the response rate to a postal questionnaire in a study screening for undiagnosed parkinsonism in people aged 65 years and over in the community. STUDY DESIGN AND SETTING: A total of 2,524 people aged 65 years and over from five general practices in Aberdeen were randomized to receive a questionnaire about the symptoms of parkinsonism printed in either colored (green) or black ink, and sent out in either a brown or white envelope. RESULTS: The overall response rate was 63.5%. There was no significant interaction between envelope and ink color. The use of green ink compared to black significantly increased the response rate from 61.4% to 65.7% (OR 1.20, 95% confidence interval 1.02, 1.41). There was no overall effect of envelope color on response rate (62.3% brown and 64.8% white, OR 0.90, 95% confidence interval 0.76, 1.06) but there was significant heterogeneity between the general practices. When this general practice-envelope interaction was accounted for, brown envelopes had a significantly lower response rate than white ones (OR 0.49). CONCLUSION: This study, along with existing evidence, has shown that the use of certain ink colors in postal questionnaires is likely to increase response rates relative to black ink. The effect of envelope color was inconsistent both within this study and between previous studies.

Aged↗

PubMed2007

Ballpoint pen inks: the quantitative analysis of ink solvents on paper by solid-phase microextraction.

We wish to describe further developments to a method previously reported on the detection of 2-phenoxyethanol in ink. The solid-phase microextraction (SPME) sampling technique, together with gas chromatography-mass spectrometry (GC-MS), has been used to quantify solvents in writing ink. In conventional approaches, the analysis of ink on documents requires some degree of destructive sampling. The methods commonly used remove ink samples from paper using a scalpel or a paper punch. To avoid document destruction, a sampling cell was constructed that allows solvents to be adsorbed directly onto the SPME fiber from the headspace above the document surface. Analytes (ink volatiles) are then desorbed from the SPME fiber on a gas chromatograph equipped with a mass selective detector (GC-MSD). With this method, it was possible to detect the presence of ink solvents on documents for a period lasting up to c. 2 years.

Journal Article↗

PubMed2004

The identification of 2-phenoxyethanol in ballpoint inks using gas chromatography/mass spectrometry--relevance to ink dating.

Developing and implementing a generally accepted procedure for the dating of ink found on documents using dynamic approaches has been a very formidable undertaking by forensic document examiners. 2-Phenoxyethanol (PE), a common volatile organic compound found in ballpoint inks, has been recognized for over a decade as a solvent that evaporates as ink ages. More recently, investigations have focused on the solvent loss ratio of PE prior to and after heating. To determine how often PE occurs in ink formulations, the authors analyzed 633 ballpoint inks utilizing a gas chromatograph/mass spectrometer. 2-Phenoxyethanol was identified in 85% (237/279) and 83% (293/354) of black and blue inks, respectively.

Journal Article↗

PubMed1977

Inking in Aplysia californica. III. Two different synaptic conductance mechanisms for triggering central program for inking.

1. In the previous two papers we described the motor elements which mediate all-or-none inking behavior in Aplysia (4) and the contribution of specific membrane properties of the ink-gland motor cells to the central program for inking (5). In the present paper we show that the central program for inking (a characteristic accelerating burst of action potentials in the motor cells) can be triggered in two different ways: 1) by means of a suprathreshold stimulus delivered to a single site on the animal; and 2) by means of two subthreshold stimuli closely spaced in time, delivered either to the same or to different sites on the animal. 2. The single suprathreshold stimulus triggers the central program primarily by means of a complex increased-conductance EPSP. The two subthreshold stimuli trigger the program by means of a complex decreased-conductance EPSP which is capable of augmenting subsequent afferent synaptic input. 3. The synaptic augmentation produced by the decreased-conductance EPSP is attributable to two properties of the EPSP: 1) it increases the input resistance of the ink-gland motor cells so that the synaptic current from afferent input onto the cells produces larger, more effective EPSP's; and 2) it increases the electrotonic coupling among the motor cells, thereby producing increased positive feedback among them. Thus, the decreased-conductance EPSP provides a novel mechanism for spatial and temporal summation.

Animals↗

PubMed2004

[Chromaticity analysis for colorants in dye-based ink-jet ink].

For ink-jet color inks used for the well-known printers, taking Canon, EPSON, HEWLETT PACKARD and LEXMARK as samples, transmittances of the ink solutions were determined, and then the chromaticity analyses were made, in order to calculate the tristimulus values and the chromatic coordinate of each color sample. Also, the gamuts, chroma values, dominant wavelengths and complementary wavelengths were obtained by using the chromatic method for the samples. In this paper, an empirical formula was suggested for the relationship between the complementary wavelengths of the three primary colors: lambda compl, M approximately equal 10/9 (lambda compl, Y) + 10 and lambda compl, M approximately equal 10/9 (lambda compl, Y) - 20. It was found that the empirical formula is well suited for matching the complementary wavelengths of the three primary colors for ink sets of the samples studied.

English Abstract↗

PubMedDate not supplied