scholarly journals Short Communication: Practical Experience with Analysis and Design of Repeat Low-Dose SHIVSF162P3 Exposure Studies in Female Pigtail Macaques with Varying Susceptibility During Menstrual Cycling

2015 ◽  
Vol 31 (11) ◽  
pp. 1166-1169 ◽  
Author(s):  
Ellen N. Kersh ◽  
Tara R. Henning ◽  
Charles Dobard ◽  
Walid Heneine ◽  
Janet M. McNicholl
Keyword(s):  
Low Dose ◽  
Short Communication ◽  
Practical Experience ◽  
Analysis And Design ◽  
Pigtail Macaques

scholarly journals Low-Dose Hepatopancreatic MDCT: Practical Experience of Applicability

2017 ◽  
pp. 28-35
Author(s):  
V. G. Aznaurov ◽  
E. V. Kondratiev ◽  
N. K. Oganesyan ◽  
G. G. Karmazanovsky
Keyword(s):  
Radiation Exposure ◽  
Iterative Reconstruction ◽  
Low Dose ◽  
Abdominal Cavity ◽  
Practical Experience ◽  
Qualitative Assessment ◽  
Pancreatic Tumors ◽  
Reconstruction Algorithms ◽  
Liver And Pancreas ◽  
Noise Data

Aims: to evaluate the possibilities of low-dose MDCT protocols in visualization of liver and pancreatic tumors.Materials and methods. 40 patients were enrolled in study and divided into 2 groups. Two scanning protocols were used, differing by the voltage on the X-ray tube-standard 120 kV, and the modified 100 kV. All studies were performed with intravenous administration of a contrast agent. The data – noise, a circumference of abdominal cavity, a relation “contrast-noise”, data of contrast strengthening of organs were evaluated. The tomograms were reconstructed using standard and iterative reconstruction algorithms. A qualitative assessment of the images was carried out according to 2 parameters – the evaluation of the whole image and the visualization of tumor on a 3-point scale.Results. Radiation exposure decreased by 31.5% using the modified protocol. The noise level did not differ with the use of standard reconstruction, but it decreased markedly using iterative reconstruction. The contrast-to-noise ratio turned out to be higher in the “100 kV” group and consistently increased with increasing levels of iterative reconstruction. Evaluations of the visualization of tumors were significantly higher in the “100 kV” group.Conclusion. The use of low-dose protocols is justified, it allows to seriously reduce the radiation exposure, improving visualization of the liver and pancreas tumors (primarily hypervascular). Application of iterative reconstruction algorithms allows achieving significant improvement in image quality and noise reduction.

Short Communication: Characteristics of Effective Immune Control of Simian/Human Immunodeficiency Virus in Pigtail Macaques

2006 ◽  
Vol 22 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Ivan Stratov ◽  
C. Jane Dale ◽  
Socheata Chea ◽  
David C. Montefiori ◽  
Robert De Rose ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Short Communication ◽  
Immune Control ◽  
Immunodeficiency Virus ◽  
Pigtail Macaques

High Susceptibility to Repeated, Low-Dose, Vaginal SHIV Exposure Late in the Luteal Phase of the Menstrual Cycle of Pigtail Macaques

2011 ◽  
Vol 57 (4) ◽  
pp. 261-264 ◽  
Author(s):  
Sundaram A Vishwanathan ◽  
Patricia C Guenthner ◽  
Carol Y Lin ◽  
Charles Dobard ◽  
Sunita Sharma ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Low Dose ◽  
High Susceptibility ◽  
Pigtail Macaques

scholarly journals Short Communication: Viremic Control Is Independent of Repeated Low-Dose SHIVSF162p3Exposures

2014 ◽  
Vol 30 (11) ◽  
pp. 1125-1129 ◽  
Author(s):  
Tara R. Henning ◽  
Debra Hanson ◽  
Sundaram A. Vishwanathan ◽  
Katherine Butler ◽  
Charles Dobard ◽  
...  
Keyword(s):  
Low Dose ◽  
Short Communication

Analysis and Design of Hydraulic System of a Hydraulically Actuated Quadruped Robot

2013 ◽  
Vol 461 ◽  
pp. 861-868
Author(s):  
Zhi Li ◽  
Hong Kai Li ◽  
Hao Zhang ◽  
Zhen Dong Dai
Keyword(s):  
Hydraulic System ◽  
Simulation Analysis ◽  
Movement Pattern ◽  
Hydraulic Cylinder ◽  
Practical Experience ◽  
Quadruped Robot ◽  
Line System ◽  
Analysis And Design ◽  
Hydraulically Actuated ◽  
Asymmetrical Hydraulic Cylinder

Abstract.Quadruped not only possess excellent kinetic speed and stability but also can adapt to various complex terrains, with the result that hydraulically actuated quadruped bionic robots with high load and outstanding adaptability have become the research hotspot. Hydraulic system, which is regarded as the dynamic part of a hydraulic quadruped robot, has a direct effect on the kinetic capability of robots. Based on dog’s structure bionics, hydraulically actuated quadruped robot was designed. In accordance with distribution modes of hydraulic cylinders which drive robot’s kinetic joints, a hydraulic oil-line system of the robot was designed in this paper. Combining the maximum design kinetic velocity, trotting movement pattern within foot’s work space was planned. Velocity curve of each joint’s hydraulic cylinder was obtained through simulation analysis of dynamic analysis software. According to the structure of asymmetrical hydraulic cylinder, minimum flux which the oil hydraulic pump theoretically requires at the robot’s maximum kinetic speed was calculated. With practical experience, the oilsource parameter which could meet the demands of hydraulic quadruped robot were determined.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Characterization of microtubules by dark-field STEM and replication

1991 ◽  
Vol 49 ◽  
pp. 152-153
Author(s):  
S.B. Andrews ◽  
R.D. Leapman ◽  
P.E. Gallant ◽  
T.S. Reese
Keyword(s):  
Protein Interactions ◽  
Low Dose ◽  
Unit Length ◽  
Dark Field ◽  
Carbon Films ◽  
Microtubule Associated Proteins ◽  
Molecular Weights ◽  
Freeze Dried ◽  
Protein Motors ◽  
Associated Proteins

As part of a study on protein interactions involved in microtubule (MT)-based transport, we used the VG HB501 field-emission STEM to obtain low-dose dark-field mass maps of isolated, taxol-stabilized MTs and correlated these micrographs with detailed stereo images from replicas of the same MTs. This approach promises to be useful for determining how protein motors interact with MTs. MTs prepared from bovine and squid brain tubulin were purified and free from microtubule-associated proteins (MAPs). These MTs (0.1-1 mg/ml tubulin) were adsorbed to 3-nm evaporated carbon films supported over Formvar nets on 600-m copper grids. Following adsorption, the grids were washed twice in buffer and then in either distilled water or in isotonic or hypotonic ammonium acetate, blotted, and plunge-frozen in ethane/propane cryogen (ca. -185 C). After cryotransfer into the STEM, specimens were freeze-dried and recooled to ca.-160 C for low-dose (<3000 e/nm2) dark-field mapping. The molecular weights per unit length of MT were determined relative to tobacco mosaic virus standards from elastic scattering intensities. Parallel grids were freeze-dried and rotary shadowed with Pt/C at 14°.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

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