Spectrographic Techniques Research Articles

The structure and composition of the eggshell and embryonic membranes of Alligator mississippiensis

SummaryThe structure and chemical composition of the eggshell and eggshell membrane of Alligator mississippiensis were investigated utilizing macroscopy, scanning electron microscopy, energy dispersive analysis by X‐rays, atomic absorption flame spectroscopy and spectrographic techniques on age known eggs fixed at daily intervals throughout the 65‐day incubation period. Macroscopic observations were also made on the structure and disposition of the extraembryonic membranes. The freshly laid alligator egg is pure white and translucent. Within 24 h of egg‐laying the embryo attaches to the top of the egg, so inducing an opaque, chalky white, central band. As incubation progresses, this band expands in length, eventually reaching the ends of the egg by about the fifth week of development. The origin and expansion of eggshell banding are multifactorial, being caused by: (1) a drying out of the eggshell due to polarization of the watery albumen towards the ends of the egg and an increase in porosity of the shell; (2) the numerous pores in the central region of the shell which render the calcite opaque; (3) the development of erosion craters which render the calcite opaque and alter the optical properties of the shell; (4) the presence of fewer mammillae at the ends of the egg; (5) a progressive decrease in the ratio of calcite crystals to organic matrix in the organic layers; and (6) the expansion of the vascular chorio‐allantoic membrane around the inside of the shell which mobilizes minerals from the latter (for use in embryonic calcification), so causing the eggshell membrane to become chalky white. The alligator egg consists of the following layers from outside in: (1) an outer densely calcified layer (100–200 μm thick) consisting of small vertically stacked calcite crystals orientated with their crystallographic c axes at right angles to the shell surface; (2) a honeycomb layer (300–400 μm thick) consisting of horizontally stacked calcite crystals with their crystallographic c axes parallel to the shell surface; (3) an organic layer (approximately 10 μm thick) containing a higher percentage of organic matrix to calcite crystals, and through which the shell cleaves and falls away from the egg shortly before hatching; (4) a mammillary layer (20–30 μm thick) which is more pronounced in the central opaque region of the shell and which attaches the latter to the eggshell membrane; and (5) an eggshell membrane (150–250 μm thick) consisting of an interwoven mesh of fibres, separated from the albumen by an amorphous limiting membrane, in which there are numerous pores. The crystals of the outer densely calcified layer undergo extrinsic acidic dissolution (by organic acids produced by nest micro‐organisms and by hydrated carbon dioxide) to produce erosion craters and cratered pore orifices. The extent, shape and depth of these craters is governed by the strict crystallographic alignment of calcite crystals in the outer densely calcified and honeycomb layers, by the anisotropic properties of these crystals and by diffusion control. These erosion craters expose at their broad bases the underlying honeycomb layer which contains large numbers of vesicular holes, interconnecting with other cavities throughout the shell. Thus, development of erosion craters renders the entire egg more porous as incubation proceeds. In addition, these craters, together with the mobilization of calcite crystals out of the organic layer for use in embryonic mineralization, progressively weaken the shell causing it to crack and cleave off the eggshell membrane and mammillary layer, so facilitating hatching. No air space is present in the alligator egg, neither are there any chalzae. The embryo has the usual amniote arrangement of extra‐embryonic membranes which are firmly fused along two longitudinally opposite ribs, so anchoring the embryo in a constant position within the shell. The structure of the alligator egg is beautifully adapted to both its function and the nesting biology of the animal. The present investigation documents for the first time in any animal: (1) extrinsic degradation of an eggshell as incubation progresses; (2) a gross change in the external appearance of an egg as development proceeds; (3) two types of shell structure (mammillae plus pores, no mammillae no pores) within different regions of the same egg; and (4) a marked change in the porosity of an egg as incubation proceeds.

Accuracy of formant frequency estimation by spectrograms and by linear prediction analysis

The accuracy of spectrographic techniques and of linear prediction analysis in measuring formant frequencies was compared. The first three-formant frequencies of ninety synthetic speech tokens were measured by three experienced spectrographic readers and by linear prediction analysis. The synthetic speech tokens were made by parallel synthesis and were chosen to represent a wide range of formant bandwidths, frequencies, and fundamental frequencies. For fundamental frequencies between 100 and 350 Hz, both methods are accurate to within approximately ±60 Hz for both first and second formants; the third formant can be measured with the same degree of accuracy by linear prediction, but only to within ±120 Hz by spectrographic means. For linear prediction analysis, accuracy does not decrease with increasing fundamental frequency, although the accuracy of both methods decreases greatly when fundamental frequency is 400 Hz or greater. These limits of measurement appear to be within the vicinity of difference limens for formant frequencies. [Supported by NINCDS Grant NS03856.]

A Numerical Approach to the Analysis of Solitary Vireo Songs

-Cluster and principal components analyses were used to represent the variation in Solitary Vireo digitized notes and song compositions. These vireos utter highly stereotyped notes which they sequence as a quasiperiodic Markov chain. Birds from the same locality sing similar compositions of note types, but vary among individuals in the morphology of their notes. Learning is probably important in the development of Solitary Vireo songs and individuals incorporate small changes in their notes. Songs of the Solitary Vireo (Vireo solitarius) consist of long sequences of separate notes, sung at the rate of 20 to 30 notes per minute, with no obvious superstructure. Many of the species in Vireo have songs of similar gross organization, but in others, several notes are coupled together forming discrete songs. Even for Solitary Vireos, notes from eastern and western populations are conspicuously different (Borror 1972). Vireos could be an extremely interesting group for studies of the evolution of vocal behaviors, but their songs are difficult to analyze by standard sound spectrographic techniques (for example, Lemon [1971] was able to detail the repertoires of only two individual Red-eyed Vireos, V. olivaceus). Vireo songs are well suited for analysis with computerized pattern recognition schemes. I have been studying some of the statistical tools useful for this new approach to bird vocalizations. In the interests of repeatability and rigor, I have employed methods by which large samples of songs from many different individuals and species can be numerically compared. In this paper, I apply cluster and principal components analyses to digitized sound frequencies, comparing Solitary Vireo notes within and among individuals from several localities in eastern North America. I compare song compositions on the basis of probability vectors of note occurrence, and show that sequencing of the notes can be represented as a Markov process. I then discuss several issues of methodology and speculate on the divergence of Solitary Vireo

Radiation effects in synthetic berlinite (AlPO4)

Electron spin resonance (ESR), electron-nuclear double resonance (ENDOR), and optical absorption have been used to investigate radiation effects in synthetic crystals of berlinite (AlPO4). Crystals from seeded and unseeded growth were included in the study and impurities in both types of samples were determined by emission spectrographic techniques. The presence of significant concentrations of Fe3+ ions was verified by ESR measurements. When the berlinite samples were irradiated at 300 K with 1.7-MeV electrons, six distinct hole-like centers were created. Thermal anneal studies revealed that four of these centers decay near 425 K and the other two decay at 550 K. All six centers exhibited a hyperfine interaction with a 100% abundant I=1/2 nucleus. The irradiation induced a light orange coloration in the crystals and optical absorption spectra revealed a band at 520 nm along with additional absorption in the ultraviolet region. When the samples were irradiated at 77 K, two additional defects were produced which are not stable at room temperature. One of these latter centers is identified as atomic hydrogen.

The growth of CdS in sealed silica capsules

Using emission and mass spectrographic techniques it has been demonstrated that carbon monoxide is evolved from a silica capsule when it is sealed-off from a vacuum system. Consequently crystals of CdS grown by sublimation down a temperature gradient in sealed, evacuated silica capsules were in fact grown in the presence of carbon monoxide at a pressure of the order of 1 Torr. At elevated temperatures the CO reacts with the CdS to form CS2 and COS. The variability in the quantity of CO evolved during seal-off accounts for the observed variations in the quantity of material transported in different growth runs. Experiments are also reported which demonstrate that silica tubing is porous to certain metallic ions when it is held at a temperature near 1150°C. Because of this effect many crystals grown in this laboratory have, in the past, been accidentally contaminated with copper.

Rare earths of the Nile Valley phosphorites, Upper Egypt

The present work is concerned with the absolute and relative abundance and distribution of the rare-earth elements (REE) in the huge phosphate deposits of the Nile Valley, Upper Egypt. Combined chemical separation—potentiometric—spectrographic techniques are used. It is suggested that the phosphatic material is the accumulator of the REE, where the crystallization degree is a controlling factor. The REE content is most probably related to the composition of the terrigenous supply of the depositional sea, rather than to its depth.

Emission Spectrographic Analysis of Surfaces with an Ion-Sputtering Source

An ion-sputtering source was installed and evaluated as an emission spectrographic source for the analysis of metal surfaces and for the determination of in-depth concentration profiles. This source generates a direct current glow discharge in a low-pressure argon atmosphere between a hollow stainless-steel anode and the sample (the cathode) and sputters material at a controlled rate from the sample surface. The resultant spectrum of the sputtered material is recorded photographically, and the analysis is completed by conventional spectrographic techniques. The power supply of the source can be operated in either a constant dc mode or a square-wave dc mode, but better repeatability and accuracy have been achieved with the square-wave dc mode. Before any significant sputtering occurs with this source, the voltage must exceed 240 Volts, the threshold sputtering voltage. The sputtering rate increases with both source current and voltage. This source has been used for the quantitative analysis of the surface of steel products and the determination of changes in composition with depth below the surface.

Thermal characterization of polymeric materials used in semiconductor die bonding

Several conductive and non-conductive epoxy systems recommended for use in microelectronic device bonding applications have been characterized by thermal analysis and spectrographic techniques. Data on such properties as degradation temperatures, weight changes as a function of temperature, coefficient of expansion, second-order transition temperature, shrinkage behavior, and peak exothermic reaction temperature of polymeric materials were determined to be important in order to optimize curing conditions for specific polymer applications. Thermal analysis has been successfully used in observing the shrinkage behavior of some conductive gold- and silver-filled epoxy resin systems and in understanding fluctuating contact resistance readings in ohmic die bonds using conductive epoxy systems.

Interstellar lines in the ultraviolet spectrum of delta Sco.

Interstellar lines arising in carbon, oxygen, silicon, and sulfur observed in the ultraviolet spectrum of zeta Oph by rocket spectrographic techniques were analyzed. Within a factor of 10, the abundances of c(+), neutral 0, and Si(+) outside the H II region surrounding zeta Oph, relative to the hydrogen abundance, are equal to solar values. The lines in neutral C and S(+) imply that the interstellar matter is distributed among several clouds as indicated by high resolution visible spectra. It is suggested that the excited C(+) ions are inside the Stromgren sphere where proton densities equal to or greater than 0.0022 cm can collisionally excite the ions at sufficient rates. Stellar absorption lines of C IV (1548.2, 1550.8A) and N V (1238.8, 1242.8A) were observed shifted to lower wavelengths, indicating stellar mass loss.

Tissue reactions to metallic wear and corrosion products in human patients.

AbstractTissues from around surgical implants have been examined by optical microscopy and electron microscopy and by electron diffraction and x‐ray spectrographic techniques. The presence of small alloy fragments and carbides worn from cobalt‐chromium total joint replacements was confirmed. These foreign bodies had been phagocytosed by macrophages and there were no indications that the tissues were damaged by their presence. In 13 of 44 specimens there were granulomatous foci related apparently to the presence of numerous minute particles of unknown composition which had elicited vigorous macrophage reactions.In tissues near stainless steel joints too there were particles of the naked alloy taken up by macrophages and again the fibrous tissue appeared unaffected.Typically the tissues near to stainless steel implants are affected by cytosiderosis. It is deduced that the iron released by corrosion from stainless steel is processed by macrophages locally and there is formed a mixture of hydrated ferric oxides similar to hemosiderin. This may be looked upon as a detoxication mechanism. There is evidence that in some specimens the limit of tissue tolerance for stored iron has been exceeded locally with consequent pathological changes.Another common deposit around stainless steel implants occurs in large plaques. It attracts giant cells and there is evidence that it is fibrotic and cytotoxic.

An evaluation of the chemical identity oe acylcarnitine esters oe hexadecanoic acids

The infrared and NMR data on the acylcarnitine esters of β-substituted hexadecanoic acids, the synthesis and metabolism of which were described previously, are discussed in view of the recent controversy regarding the identity of these compounds. The chemical purity and identity of the compounds in question have been assessed on the basis of chemical degradation, chromatographie and spectrographic techniques. It is concluded that these compounds were chemically and stereochemically authentic.

Calculation of Detection Limits in Spectrographic Analysis

AbstractMethods to calculate detection limits of spectrographic techniques in terms of blank and background are described. Detection limits of “point‐to‐plane” and “plane‐to‐plane” spark excitation for spectrographic determination of Yttrium in solution are compared. The influence of electrode shape and of CsCl‐carrier addition is discussed.

Interstellar Lines in the Ultraviolet Spectrum of Zeta Ophiuchi

Interstellar lines arising in carbon, oxygen, silicon, and sulfur observed in the ultraviolet spectrum of zeta Oph by rocket spectrographic techniques were analyzed. Within a factor of 10, the abundances of c(+), neutral 0, and Si(+) outside the H II region surrounding zeta Oph, relative to the hydrogen abundance, are equal to solar values. The lines in neutral C and S(+) imply that the interstellar matter is distributed among several clouds as indicated by high resolution visible spectra. It is suggested that the excited C(+) ions are inside the Stromgren sphere where proton densities equal to or greater than 0.0022 cm can collisionally excite the ions at sufficient rates. Stellar absorption lines of C IV (1548.2, 1550.8A) and N V (1238.8, 1242.8A) were observed shifted to lower wavelengths, indicating stellar mass loss.

The determination of trace metals in microlitre samples by plasma torch excitation: With special reference to oil, organic compounds and blood samples

A method is described for multi-element analysis in which microlitre samples of solutions of inorganic and organic materials are used. Samples are introduced into the high-frequency plasma torch by means of a small heated nebulizer, and the emission is recorded by conventional spectrographic techniques. Detection limits for various metals are in the range l0 −9–10 −10 g; at the 10 −9 level, precision is of the order of 5%. Examples of the application of the method to the determination of trace elements in oil, organic compounds and blood are given.

An Economical High Vacuum Water Cooled Sputtering Cathode Assembly and Feedthrough

A very economical high vacuum feedthrough and water cooled cathode pedestal and dark space shield assembly were designed and built in our laboratories without requiring any model shop time and without purchasing any expensive material from the outside. The effectiveness of this design to sputter alloys was verified by x-ray spectrographic techniques. During a typical supttering run 5000 V dc at 150 mA could be handled by this cathode assembly and feedthrough without difficulty. This particular feedthrough design was tested successfully in the 10−7 Torr range.

Measurements of spallation cross sections for 590 MeV protons on thin targets of copper, nickel, iron and aluminum

Yields have been measured of approximately 50 spallation products from 590 MeV protons on thin natural targets of copper, nickel, iron and aluminum. Non-destructive γ-ray spectrographic techniques have been used in the analyses allowing yield determinations for the short-lived (i.e., T 1 2 ≧ 10 s ) spallation products. Measured yields are compared to yields calculated using the current formulae.

Chemical and mineral composition of the Lost City meteorite

The Lost Gity meteorite was analyzed by X-ray diffraction and optical emission spectrographic techniques. The major-element data combined with the olivine composition (fayalite 18.1%) and the concentrations of kamacite (17%) provide enough information to place the Lost City meteorite in the H chemical group. The X-ray diffraction scans indicate the meteorite probably belongs to the 5 petrologic group.

Marine algae of the Champlain Sea episode near Ottawa

Examination of a marine algal deposit from the Champlain Sea (10 800 ± 150 y old) found by Mott (1968) revealed that it is composed mainly of well preserved blades of Laminaria. These were associated with another brown species not susceptible of definite identification and a single fragment of a foliose red species, probably Rhodymenia.Filaments of Audouinella membranacea were found in hydroids in the deposit and another small red alga, Acrochaetium identified. The presence of several plant pigments was indicated by chromatographic and spectrographic techniques.

Optics at Langley Research Center

The specialized tools of optics have played an important part in Langley's history of aeronautical and space research. Schlieren systems for photographing aeronautics and space models in wind-tunnel investigations have contributed to the available knowledge of aerodynamics. Optics continues to be an important part of Langley's research program, including new techniques for measuring the sensitivity of photomultiplier tubes, spectrographic techniques for radiation measurements of wind-tunnel models, research into large orbiting telescopes, horizon definition by ir radiation measurements, spectra of natural and artificial meteors, measurement of clear air turbulence utilizing lasers, and many others.

ELECTRON DENSITIES AND TEMPERATURES IN A CLOSE-SPACED CESIUM PLASMA DIODE

Spectrographic techniques have been used to determine electron temperatures and densities in the interelectrode plasma of a close-spaced high-current cesium plasma diode. These results were obtained from the relative intensity of the radiative recombination continuum and measured line-widths, respectively, of cesium. The diode was operated at two short-circuit current conditions (∼15 and 18 A/cm2) with an interelectrode spacing of 0.25 mm. Contrary to some theories, these results indicate that steep temperature gradients do exist in the plasma and that maximum electron temperatures are 2800°K.