Accurate Technique for Electrical Permittivity Measurement of Biological Tissue Specimens at Low Frequencies

2019 ◽  
Vol 68 (7) ◽  
pp. 2479-2490
Author(s):  
Seyyed M. Hesabgar ◽  
Reza Jafari ◽  
Abbas Samani
Keyword(s):  
Biological Tissue ◽  
Low Frequencies ◽  
Permittivity Measurement ◽  
Electrical Permittivity ◽  
Tissue Specimens

Application of Laser Ablation-ICPMS to the Spatially Resolved Micro-Analysis of Biological Tissue

1994 ◽  
Vol 48 (11) ◽  
pp. 1321-1325 ◽  
Author(s):  
S. Wang ◽  
R. Brown ◽  
D. J. Gray
Keyword(s):  
Laser Ablation ◽  
Cross Sections ◽  
Biological Tissue ◽  
Inductively Coupled Plasma ◽  
Laser Energy ◽  
Rat Kidney ◽  
High Sensitivity ◽  
Elemental Distribution ◽  
Inductively Coupled ◽  
Tissue Specimens

Laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) has been applied as a method to determine elemental distribution in biological tissue specimens, providing spatial resolution down to 30 μm with the use of an infrared laser beam. Instrument operating parameters such as the laser energy and “dry plasma” tuning have been optimized to provide the high sensitivity and stability required for this type of analysis. In this work, “natural” internal standards (e.g., calcium and magnesium) have been investigated in an effort to establish and minimize the influence of signal variation associated with the instrumentation and the density of the samples themselves. Specimens studied include fish scales (for “elemental tagging”), rat kidney cross sections, and pig femur (to examine variation in the chemistry of the blood/bone interface).

Advances in Microprobe Analysis Applied to Muscle, Nerve and Gland

1982 ◽  
Vol 40 ◽  
pp. 404-407
Author(s):  
T. E. Hutchinson ◽  
D. E. Johnson ◽  
A. C. Lee ◽  
E. Y. Wang
Keyword(s):  
Biological Tissue ◽  
Microprobe Analysis ◽  
Physiological State ◽  
External Environment ◽  
Physiological Relevance ◽  
Muscle Nerve ◽  
Technique Development

Microprobe analysis of biological tissue is now in the end phase of transition from instrumental and technique development to applications pertinent to questions of physiological relevance. The promise,implicit in early investigative efforts, is being fulfilled to an extent much greater than many had predicted. It would thus seem appropriate to briefly report studies exemplifying this, ∿. In general, the distributions of ions in tissue in a preselected physiological state produced by variations in the external environment is of importance in elucidating the mechanisms of exchange and regulation of these ions.

Ultrastructural Studies on Genital Infection with the Chlamydial Agent of Guinea Pig Inclusion Conjunctivitis

1977 ◽  
Vol 35 ◽  
pp. 352-353
Author(s):  
B. L. Soloff ◽  
A. L. Barron ◽  
H. J. White ◽  
R. G. Rank
Keyword(s):  
Guinea Pig ◽  
Sexual Contact ◽  
Chlamydia Psittaci ◽  
Genital Infection ◽  
Major Site ◽  
Ultrastructural Studies ◽  
Tissue Specimens ◽  
Guinea Pig Model ◽  
Adequate Tissue ◽  
Genital Tissue

Chlamydial organisms (specifically C. trachomatis) have been implicated as a frequent cause of genital infection in the human (1). Study of the histo- pathological aspects of such infections has been impeded because of difficulties in obtaining adequate tissue specimens and the lack of a suitable experimental host. In 1964, Murray (2) isolated the causative agent of guinea pig inclusion conjunctivitis which possesses similarities to human inclusion conjunctivitis. This guinea pig organism was found to be a member of the Chlamydia psittaci subgroup and was designated as the Gp-ic agent. Male guinea pigs have been successfully infected with Gp-ic by intraurethral inoculation. Transmission of the infection to the female by sexual contact has been demonstrated (3). We are not aware of any ultrastructural studies to date concerning the development of this agent in genital tissue.Studies in our laboratory have established that, in our guinea pig model, the cervix is the major site of injection.

Electron Microscopic Examination of a Transplantable Rat Mammary Carcinoma

1968 ◽  
Vol 26 ◽  
pp. 20-21
Author(s):  
S. Shirahama ◽  
G. C. Engle ◽  
R. M. Dutcher
Keyword(s):  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Electron Microscopic Examination ◽  
Undifferentiated Carcinoma ◽  
Uranyl Acetate ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
North West ◽  
X Irradiation ◽  
Tissue Specimens

A transplantable carcinoma was established in North West Sprague Dawley (NWSD) rats by use of X-irradiation by Engle and Spencer. The tumor was passaged through 63 generations over a period of 32 months. The original tumor, an adenocarcinoma, changed into an undifferentiated carcinoma following the 19th transplant. The tumor grew well in NWSD rats of either sex at various ages. It was invariably fatal, causing death of the host within 15 to 35 days following transplantation.Tumor, thymus, spleen, and plasma from 7 rats receiving transplants of tumor at 3 to 9 weeks of age were examined with an electron microscope at intervals of 8, 15, 22 and 30 days after transplantation. Four normal control rats of the same age were also examined. The tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and embedded in Epon. The plasma was separated from heparanized blood and processed as previously described for the tissue specimens. Sections were stained with uranyl acetate followed by lead citrate and examined with an RCA EMU-3G electron microscope.

Complementary Z-Contrast Imaging and Digital Image Processing

1985 ◽  
Vol 43 ◽  
pp. 304-305
Author(s):  
K. N. Colonna ◽  
G. Oliphant
Keyword(s):  
Image Processing ◽  
Heavy Metal ◽  
Digital Image Processing ◽  
Digital Image ◽  
Biological Tissue ◽  
Biological Imaging ◽  
Tissue Preparation ◽  
Contrast Imaging ◽  
Imaging Tool ◽  
Z Contrast

Harmonious use of Z-contrast imaging and digital image processing as an analytical imaging tool was developed and demonstrated in studying the elemental constitution of human and maturing rabbit spermatozoa. Due to its analog origin (Fig. 1), the Z-contrast image offers information unique to the science of biological imaging. Despite the information and distinct advantages it offers, the potential of Z-contrast imaging is extremely limited without the application of techniques of digital image processing. For the first time in biological imaging, this study demonstrates the tremendous potential involved in the complementary use of Z-contrast imaging and digital image processing.Imaging in the Z-contrast mode is powerful for three distinct reasons, the first of which involves tissue preparation. It affords biologists the opportunity to visualize biological tissue without the use of heavy metal fixatives and stains. For years biologists have used heavy metal components to compensate for the limited electron scattering properties of biological tissue.

The S-SH Confusion Test and the Effects of Frequency Lowering

2019 ◽  
Vol 62 (5) ◽  
pp. 1486-1505
Author(s):  
Joshua M. Alexander
Keyword(s):  
Cognitive Processing ◽  
Hearing Aids ◽  
Response Times ◽  
Nonlinear Frequency ◽  
Low Frequencies ◽  
Frequency Compression ◽  
Negative Side ◽  
Minimal Word ◽  
Low Pass ◽  
Negative Side Effects

PurposeFrequency lowering in hearing aids can cause listeners to perceive [s] as [ʃ]. The S-SH Confusion Test, which consists of 66 minimal word pairs spoken by 6 female talkers, was designed to help clinicians and researchers document these negative side effects. This study's purpose was to use this new test to evaluate the hypothesis that these confusions will increase to the extent that low frequencies are altered.MethodTwenty-one listeners with normal hearing were each tested on 7 conditions. Three were control conditions that were low-pass filtered at 3.3, 5.0, and 9.1 kHz. Four conditions were processed with nonlinear frequency compression (NFC): 2 had a 3.3-kHz maximum audible output frequency (MAOF), with a start frequency (SF) of 1.6 or 2.2 kHz; 2 had a 5.0-kHz MAOF, with an SF of 1.6 or 4.0 kHz. Listeners' responses were analyzed using concepts from signal detection theory. Response times were also collected as a measure of cognitive processing.ResultsOverall, [s] for [ʃ] confusions were minimal. As predicted, [ʃ] for [s] confusions increased for NFC conditions with a lower versus higher MAOF and with a lower versus higher SF. Response times for trials with correct [s] responses were shortest for the 9.1-kHz control and increased for the 5.0- and 3.3-kHz controls. NFC response times were also significantly longer as MAOF and SF decreased. The NFC condition with the highest MAOF and SF had statistically shorter response times than its control condition, indicating that, under some circumstances, NFC may ease cognitive processing.ConclusionsLarge differences in the S-SH Confusion Test across frequency-lowering conditions show that it can be used to document a major negative side effect associated with frequency lowering. Smaller but significant differences in response times for correct [s] trials indicate that NFC can help or hinder cognitive processing, depending on its settings.

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