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PubMed1997

Effect of particle sizes in India ink on its use in evaluation of apical seal.

We investigated the use of India ink as an indicator of root canal sealing ability. Sealing ability is one of the most important factors required of root canal cements. Various dyes have been used for this purpose. Methylene blue, radioisotopes and India ink have all been tried. However, there is no evidence that India ink is suitable as an indicator. We measured the particle size distribution of India ink to determine how this factor affects test results. In addition, we observed the surface texture of an experimentally developed calcium phosphate sealer and a commercially available root canal sealer using SEM. We found that a portion of the India ink particles were smaller than cracks on the two sealer surfaces, indicating, that India ink could pass through these cracks. We concluded that India ink is suitable as an indicator of root canal seal.

Calcium Phosphates↗

PubMed1993

The ESEM used to image crystalline structures of polymers and to image ink on paper.

This article describes two cases in which the advantages of the ESEM have been exploited in unanticipated ways. First, we have found that etching occurs as the electron beam scans the surface of uncoated polymers in the ESEM. The surface topography caused by this etching, as seen in ESEM images, reflects the morphology of crystalline structures in the polymers. This technique has been valuable in the study of such textures in polymers. The second application is related to our use of the ESEM in support of research on the deinking of paper. In this effort we have learned that an unconventional contrast mechanism can be used during ESEM imaging to distinguish between inked and non-inked areas of newsprint. Under usual operating conditions, ESEM imaging does not distinguish between inked and non-inked areas. However, at relatively low sample chamber pressures the non-inked areas appear brighter than inked areas in ESEM images.

Crystallization↗

PubMed2002

Analysis of food packaging UV inks for chemicals with potential to migrate into food simulants.

Ultraviolet (UV) inks are an alternative formulation system to the more usual paste or liquid inks (oils or solvents based) that dry mainly by evaporation or penetration into the printed substrate. Based on acrylic acid chemistry, UV inks dry (the exact term is 'curing') by the chemical process of photopolymerization. Their composition (acrylate monomers and oligomers together with photo-initiators) exposed to UV emission lamps on the printing press units enable the transformation of the freshly printed ink layer into a tack-free film. For UV inks intendedfor primary food packaging, special care has to be paid to potential migrating species like small photo-initiator molecules and acrylate monomers not cross-linked in the formed network. The paper presents chromatographic methods to ascertain the level of ink ingredients potentially available to migrate into food simulants (migration tests). GC/MS was employed to quantify the levels of photo-initiators or acrylic esters (acrylates).

Acrylates↗

PubMed2003

Calibration of a radioactive ink-based stack phantom and its applications in nuclear medicine.

This paper describes a stack phantom useful for imaging complex activity distributions. It is based on images printed with radioactive ink using a commercial ink-jet printer. The application for the phantom is in the evaluation of planar and SPECT scintillation camera images and for validation of Monte Carlo simulated images. The accuracy in generating the activity distributions on paper sheets is especially important. Here we describe the calibration procedure for the ink-jet printer. The goal of the printer calibration is to find the relationship between the digital image count (voxel grey level) and its corresponding activity on the paper sheets (radioactivity). The relationship between the voxel grey level and the radioactivity on the paper sheets (measured by scanning technique and well counter) was found to be logarithmic, and a 3rd degree polynomial was found to fit the relationship. The distribution of radioactivity in the ink cartridge was investigated by pinhole SPECT. The distribution of (99m)Tc solution was found to be homogeneous in the ink solution. Experimental studies were done directly on Monte Carlo simulated heart images from the NCAT phantom. The result showed that the simulated images are similar to the images measured using the ink-jet technique. This stack phantom could be a promising solution with an advantage that the exact geometry generated in Monte Carlo could be imitated in the phantom. The phantom is a very flexible device and clearly much more versatile than conventional phantoms which have a fixed geometry and spatial limitation.

Calibration↗

PubMed1981

Filling of microcirculation in skeletal muscles during timed India ink perfusion.

Lower leg muscles of anesthetized rabbits were perfused in situ with heparinized India ink at flows and pressures comparable to normal resting levels of 4 ml.min-1.100 g-1). Paired cross sections were counterstained with eosin to show ink-containing microvessels and reacted for alkaline phosphate to show all vessels. The fraction of microvessels filled with ink (Fi) increased progressively with perfusion time. At 3.5 s, mean Fi for the muscles studied fell between 0.12 and 0.19. At 60-90 s, the following levels were reached: medial gastrocnemius 0.74, lateral gastrocnemius 0.76, tibialis anterior 0.59, and soleus 0.80. The number of open capillaries and their distribution of flow velocities can be inferred from such data only if the perfusion rate is known or by recourse to a specified anatomic model. The time course of ink appearance shows best agreement with 60-80% of the vessels open and accessible to ink, with microvascular transit times ranging from less than 3 to greater than 30 s. If microvascular path lengths are assumed to be uniform, the range of velocities must be four times to one-fourth the mean, with 15-30% of the microvessels perfused at velocities equal to or greater than the mean. Alternatively, if microvascular velocity is assumed uniform, flow path lengths must vary from one-fourth to four times the average. Anatomic measurements of other suggest that less than one-half the variability in ink transit is attributable to differences in microvascular length. Thus both length and velocity must vary among alternate arteriovenous pathways.

Animals↗

PubMed2006

Titanium, a major constituent of blue ink, causes resistance to Nd-YAG (1064 nm) laser: results of animal experiments.

A blue tattoo is more resistant to laser therapy than black or brown tattoos. This study aimed to confirm titanium as a key response-disturbing constituent in a blue tattoo ink after Nd-YAG (1064 nm) laser treatment by animal experiments. Rabbits' backs were tattooed with four ink colours, and the Nd-YAG (1064 nm) laser was used to remove the tattoos. The response to the laser treatment in the rabbits was evaluated and electron microscopic studies were also performed. Excellent to fair responses were observed for the black, brown and dark brown inks, but the blue ink responded poorly to the laser. Histological examination indicated that the blue pigments were unchanged even after the laser treatment. Quantitative energy dispersive spectrometry revealed that blue ink contained high amounts of titanium. Our animal experiments confirm that a blue tattoo ink containing titanium, is a key element in poor response to the Nd-YAG laser.

Animals↗

PubMedDate not supplied

[Differentiation of ballpoint pen inks by thermodesorption and gas chromatography-mass spectrometry].

Differentiation and classification of ink entries with dated samples of a reference collection are important aspects in the examination of questioned documents. Classification of writing inks is presently achieved by analysis of dyes and colorants contained in the ink. This technique has its limitations in newly developed ink formulations with identical dye composition but differing in their solvents and binder resins. This paper introduces a method for the determination of solvents and binder resins of an ink sample directly from paper without sample preparation. This aim is accomplished by thermodesorption of the sample followed by gas chromatography/mass spectroscopy. The method was tested on numerous samples of ballpoint pen inks, which were subsequently grouped into several solvent and resin subgroups. A case study shows the applicability of the newly developed method.

Adsorption↗

PubMed2005

[Determination of the writing age of blue ballpoint ink by gas chromatography].

A method of identifying the writing age of blue ballpoint ink has been established for imperative demand of forensic laboratory. The content of the volatile component in blue ballpoint ink was determined by gas chromatography (GC). The absorbance of the dye in the blue ballpoint ink was measured by ultraviolet-visible spectrometry (UV-Vis). A writing age curve of the blue ballpoint ink has been established by the ratio of the content of the volatile components and the dye, based on the identification of 74 kinds of blue ballpoint inks, from both domestic and international origins. The change of benzyl alcohol or phenoxyethyl alcohol was tested with the writing age. Blue ballpoint inks of different kinds were detected and the repeatability of the experiment was investigated. The results indicated that the method is reliable and systematic, and especially suitable for practical cases.

Benzyl Alcohol↗

PubMed1995

Use of EPR oximetry with India ink to measure the pO2 in the liver in vivo in mice.

The partial pressure of oxygen (pO2) of the liver in vivo in unanesthetized mice was determined using electron paramagnetic resonance (EPR) oximetry with India ink. The EPR spectra were obtained using a low-frequency (1.2 GHz) EPR spectrometer with a loop gap cavity resonator. The line width of the India ink used in this experiment was reversibly broadened by oxygen and was particularly sensitive to pO2 below 30 torr. After the administration of India ink into the tail vein, the India ink particles were taken up mainly by Kupffer cells in the liver and in part by phagocytes in the spleen. The pO2 measured in the normal liver was about 14 torr and was constant for the 2-week experimental period. The pO2 decreased when measured at 1, 2, and 6 days after treatment with hepatotoxin (carbon tetrachloride (CCl4)); within 2 weeks, it returned almost to the initial level. Measurements by EPR at sacrifice of controls and CCl4-treated mice indicated that more than 90% of the India ink went to the liver; the spleen contained 4.7% of total amount in control mice and 8.8% in CCl4-treated mice when measured 2 weeks after the treatment. These data indicate the usefulness of India ink for measuring the pO2 of the liver in vivo and that the pO2 in the Kupffer cells is decreased when the liver is damaged by CCl4.

Animals↗

PubMed1988

India ink staining of proteins on nylon and hydrophobic membranes.

India ink was found to be an acceptable stain for proteins blotted or dotted onto positively charged nylon or hydrophobic membranes. The hydrophobic membrane, Immobilon, was an outstanding matrix for binding proteins and displayed low levels of background staining. The least amount of protein detected by india ink staining was between 1.0 and 10 ng. India ink staining of proteins on nylon membranes is an easy, inexpensive, and quick method for the unequivocal detection of both standards and unknowns in the same blot. However, inks, ink concentrations, fixing conditions, staining times, pH, washing conditions, and membrane lots all need to be controlled to achieve maximum sensitivity for protein detection following india ink staining.

Blotting, Western↗

PubMed2006

Control of colloidal particle deposit patterns within picoliter droplets ejected by ink-jet printing.

Particle deposit morphologies that resulted from evaporating ink-jetted microdroplets were controlled by varying the ink compositions and concentrations. The ink was a well-dispersed aqueous dispersion of monodisperse silica microspheres. Silica particles suspended in the microdroplet undergo self-assembly upon the evaporation of the solvent. A ringlike deposit of the self-assembled silica particles was produced from the water-based ink, while a uniform two-dimensional monolayer with a well-ordered hexagonal structure was obtained from the mixed-solvent-based inks. Variations in the deposit patterns can be explained in terms of competing effects between the convective and Marangoni flows, which vary with the types of the high-boiling-point solvent added to the ink. The macroscopic shape and microstructure of the silica colloidal deposits were observed by SEM, AFM, and a confocal microscope.

Journal Article↗

PubMed2006

Heavyweight dendritic inks for positive microcontact printing.

Poly(propylene imine) dendrimers with dialkyl sulfide end groups were prepared and developed as inks for positive microcontact printing ((+)muCP) on gold. Long (C10H21-S-C10H20-), medium (C3H7-S-C4H8-), and short (CH3-S-CH2-) dialkyl sulfide end groups were attached to second- and third-generation PPI dendrimers to create a family of dendritic sulfides. The dendritic inks flatten upon adsorption and form monolayers on gold. (+)muCP was performed on gold using commercially available poly(dimethylsiloxane) as stamp material and n-octadecanethiol as etch resist. The gold beneath the dendrimers was selectively etched away with an acidic Fe(NO3)3/thiourea solution to give the positive copy of the original master pattern. The multivalent sulfide attachment and the relatively high molecular mass of these dendrimers ensured minimal lateral ink spreading and thus optimal feature reproducibility. Contact times were varied to analyze the spreading rates of the dendritic inks. The spreading rates of the dendritic inks were found to be much lower than that of pentaerythritol tetrakis(3-mercaptopropionate). (+)muCP with the new inks was extended to submicrometer features. Optical microscopy, scanning electron microscopy, and atomic force microscopy were used to characterize the etched samples. Lines with a width of 100 nm were faithfully replicated with the third-generation dendrimers bearing medium (C3-S-C4-) end groups.

Journal Article↗

PubMed2001

Applicability of surface-enhanced resonance Raman scattering for the direct discrimination of ballpoint pen inks.

In situ surface-enhanced resonance Raman spectroscopy (SERRS) with excitation at 685 nm is suitable for the direct discrimination of blue and black ballpoint pen inks on paper. For black inks, shorter excitation wavelengths can also be used. For blue inks, SERRS at 514.5 and 457.9 nm does not provide adequate discriminative power. At these excitation wavelengths, the SERRS signals of the Methyl Violet derivatives present in inks easily dominate the overall spectrum because of resonance enhancement and preferential interaction with silver sol particles. At 685 nm, this problem is not encountered as the Methyl Violet derivatives do not show resonance enhancement, while other components may still exhibit resonance. Thirteen blue and thirteen black ink lines were examined. For the blue and black inks, on the basis of the 685 nm SERR spectra, eight and six groups of spectra, respectively, could be distinguished. This discrimination largely agrees with information from thin layer chromatography (TLC) experiments, although some differences in group compositions are found. The in situ SERR spectra show good repeatability with regard to the Raman frequencies, band shapes and relative intensities of the spectral bands. However, absolute intensities cannot be used for discrimination purposes.

Journal Article↗

PubMed2000

N-Methyl-D-aspartate receptor stimulation activates tyrosinase and promotes melanin synthesis in the ink gland of the cuttlefish Sepia officinalis through the nitric Oxide/cGMP signal transduction pathway. A novel possible role for glutamate as physiologic activator of melanogenesis.

The tyrosinase-catalyzed conversion of l-tyrosine to melanin represents the most distinctive biochemical pathway in the ink gland of the cuttlefish Sepia officinalis; however, the molecular mechanisms underlying its activation have remained so far largely uncharted. In this paper we demonstrate for the first time that l-glutamate can stimulate tyrosinase activity and promote melanin synthesis in Sepia ink gland via the N-methyl-d-aspartate (NMDA) receptor/NO/cGMP signal transduction pathway. Incubation of intact ink glands with either l-glutamate or NMDA resulted in an up to 18-fold increase of tyrosinase activity and a more than 6-fold elevation of cGMP levels. Comparable stimulation of tyrosinase was induced by an NO donor and by 8-bromo-cGMP. An NMDA receptor antagonist, NO synthase (NOS) inhibitors, and a guanylate cyclase blocker suppressed NMDA-induced effects. Immunohistochemical evidence indicated that enhanced cGMP production was localized largely in the mature part of the ink gland. Increased de novo synthesis of melanin was demonstrated in NMDA- and NO-stimulated ink glands by a combined microanalytical approach based on spectrophotometric determination of pigment levels and high performance liquid chromatography quantitation of pyrrole-2,3, 5-tricarboxylic acid, a specific melanin marker, in melanosome-containing fractions. These results fill a longstanding gap in the understanding of the complex biochemical mechanisms underlying activation of melanogenesis in the mature ink gland cells of S. officinalis and disclose a novel physiologic role of the excitatory neurotransmitter glutamate mediated by the NMDA receptor/NO/cGMP signaling pathway.

Animals↗

PubMed2000

Randomized comparative study of indocyanine green and India ink for colonic tattooing: an animal survival study.

Indocyanine green has been reported previously as a useful agent for colonic tattooing, but its durability, ease of use, cost, and safety have not been compared with India ink. Eight pigs were randomized to colonic tattooing using sterile indocyanine green or India ink injected through tandem filters. The animals were recovered and killed after 2 weeks and were examined. All animals survived the study period with no complications. We identified 17 of 29 (59%) indocyanine green tattoos and 48 of 52 (92%) India ink tattoos at autopsy (p = 0.0003). Histologic reactions were mild and were distributed similarly in each group and the intensity of the tattoos diminished similarly in both groups. Although indocyanine green was slightly more expensive, it was easier to handle compared with India ink. Both indocyanine green and India ink tattoos cause only mild histologic reaction in the swine colon when examined 2 weeks after injection. India ink is superior to indocyanine green, when used for colonic tattooing.

Animals↗

PubMed2007

Differentiation of blue ballpoint pen inks by laser desorption ionization mass spectrometry and high-performance thin-layer chromatography.

The differentiation of inks on a questioned document can highlight a fraudulent insertion and is usually carried out by optical comparison and thin-layer chromatography (TLC). Laser desorption ionization mass spectrometry (LDI-MS) may also be used for the analysis of dyes from ink. This analytical technique was compared with a standard method of high-performance TLC (HPTLC) according to their capacity to differentiate blue ballpoint inks. Ink entries on paper from 31 blue ballpoint pens have been analyzed and their dye ink formulations compared. The pens were classified into 26 classes by LDI-MS against 18 for HPTLC. LDI-MS proved to be a more powerful method for differentiating ink formulations because it provides information about dye structures (molecular weights) and relative quantification of dye classes (peak areas). Sample preparation was minimal and analysis time was short in contrast to the more complex extraction, application, and development steps of the HPTLC method. However, only basic dyes and pigments were identified using positive mode LDI-MS, while HPTLC did yield additional information about acid dyes.

Journal Article↗

PubMed1979

Biophysical mechanisms contributing to inking behavior in Aplysia.

1. The release of ink from the ink gland of Aplysia californica in response to noxious stimuli is mediated by three electrically coupled motor neurons, L14A, L14B, L14C, whose cell bodies are located in the abdominal ganglion. The initial synaptic input to the ink motor neurons is relatively ineffective in firing the cells. As a result, a pause of 1--3 s often occurs before the cells attain their maximum firing frequency and cause the release of ink. Using current and voltage-clamp techniques we have analyzed the mechanisms underlying the firing pattern of these cells. 2. The presence of a fast transient K+ current appears to play an important role in mediating the firing pattern of the ink motor neurons. Their high resting potential (-75 mV) ensures that the steady-state level of inactivation of the conductance channels for the fast K+ current will normally be low. Thus a train of EPSPs or a depolarizing current pulse can activate this current maximally, thereby reducing the initial effectiveness of the excitatory input. 3. In addition to the fast transient K+ current, four other currents were identified: 1) a fast transient tetrodotoxin-sensitive inward current, presumed to be carried by Na+; 2) a slower tetrodotoxin-insensitive inward current, presumed to be carried by Ca2+; 3) a slow transient outward tetraethylammonium- (TEA) sensitive current; and 4) a very slow TEA-insensitive outward current. 4. A decreased conductance EPSP, which turns on over a several-second period, contributes to a late acceleration of spike discharge in the L14 cells. 5. The results suggest that a unique combination of biophysical properties of the L14 cells and the features of the synaptic input cause them to act as a low-pass filter in the reflex pathway for inking. Their high resting potential, which ensures minimal inactivation of the fast transient K+ current channel, makes these cells preferentially responsive to strong and long-lasting stimuli. The delayed recruitment of a decreased conductance EPSP augments the tendency of the L14 cells to fire in an accelerating burst pattern.

Aggression↗

PubMed2001

Light scattering and ink penetration effects on tone reproduction.

Light scattering, or the so-called Yule-Nielsen effect, and ink penetration into the substrate paper play important roles in tone reproduction. We develop a framework in which the influences of both of these effects on the reflectance and tristimulus values of a halftone sample are investigated. The properties of the paper and the ink and their bilateral interaction can be parameterized by the reflectance Rp(o) of the substrate paper, the transmittance Ti of the ink layer, the parameter gamma describing the ink penetration, and p describing the Yule-Nielsen effect. We derive explicit expressions that relate the reflectance of the ink dots (Ri), the paper (Rp) and the halftone image (R) as functions of these parameters. We also describe the optical dot gain as a function of these parameters. We further demonstrate that ink penetration leads to a decrease in optical dot gain and that scattering in the paper results in the printed image's being viewed as more saturated in color.

Journal Article↗