The University of Wisconsin X-ray lithography beamline: First results

1986 ◽  
Vol 246 (1-3) ◽  
pp. 681-686 ◽  
Author(s):  
B. Lai ◽  
G. Mitchell ◽  
G.M. Wells ◽  
F. Cerrina
Keyword(s):  
X Ray ◽  
University Of Wisconsin ◽  
First Results ◽  
The University

Development of Standard X-Ray Beams for Calibration of Radiobiology Cabinet and Conformal Irradiators

2021 ◽  
Author(s):  
Emily J. King ◽  
Natalie N. Viscariello ◽  
Larry A. DeWerd
Keyword(s):  
Monte Carlo Code ◽  
X Rays ◽  
Energy Agency ◽  
X Ray ◽  
Measurement Models ◽  
Dose Determination ◽  
University Of Wisconsin ◽  
Free Air ◽  
Accurate Dose ◽  
The University

This work seeks to develop standard X-ray beams that are matched to radiobiology X-ray irradiators. The calibration of detectors used for dose determination of these irradiators is performed with a set of standard X rays that are more heavily filtered and/or lower energy, which leads to a higher uncertainty in the dose measurement. Models of the XRad320, SARRP, and the X-ray tube at the University of Wisconsin Medical Radiation Research Center (UWMRRC) were created using the BEAMnrc user code of the EGSnrc Monte Carlo code system. These models were validated against measurements, and the resultant modeled spectra were used to determine the amount of added filtration needed to match the X-ray beams at the UWMRRC to those of the XRad320 and SARRP. The depth profiles and half-value layer (HVL) simulations performed using BEAMnrc agreed to measurements within 3% and 3.6%, respectively. A primary measurement device, a free-air chamber, was developed to measure air kerma in the medium energy range of X rays. The resultant spectra of the matched beams had HVL's that matched the HVL's of the radiobiology irradiators well within the 3% criteria recommended by the International Atomic Energy Agency (IAEA) and the average energies agreed within 2.4%. In conclusion, three standard X-ray beams were developed at the UWMRRC with spectra that more closely match the spectra of the XRad320 and SARRP radiobiology irradiators, which will aid in a more accurate dose determination during calibration of these irradiators.

Control of jaw orientation and position in mastication and speech

1994 ◽  
Vol 71 (4) ◽  
pp. 1528-1545 ◽  
Author(s):  
D. J. Ostry ◽  
K. G. Munhall
Keyword(s):  
Sagittal Plane ◽  
Joint Space ◽  
Start Time ◽  
Jaw Movements ◽  
X Ray ◽  
University Of Wisconsin ◽  
Trial Basis ◽  
Average Rotation ◽  
Jaw Position ◽  
The University

1. The kinematics of sagittal-plane jaw motion were assessed in mastication and speech. The movement paths were described in joint coordinates, in terms of the component rotations and translations. The analysis focused on the relationship between rotation and horizontal translation. Evidence was presented that these can be separately controlled. 2. In speech, jaw movements were studied during consonant-vowel utterances produced at different rates and volumes. In mastication, bolus placement, compliance, and size as well as chewing rate were manipulated. Jaw movements were recorded using the University of Wisconsin X-ray microbeam system. Jaw rotation and translation were calculated on the basis of the motion of X-ray tracking pellets on the jaw. 3. The average magnitudes of jaw rotation and translation were greater in mastication than in speech. In addition, in speech, it was shown that the average rotation magnitude may vary independent of the horizontal translation magnitude. In mastication, the average magnitude of vertical jaw translation was not dependent on the magnitudes of jaw rotation or horizontal jaw translation. 4. The magnitude of rotation and horizontal jaw translation tended to be correlated when examined on a trial by trial basis. Some subjects also showed a correlation between jaw rotation and vertical jaw translation. However, the proportion of variance accounted for was greater for all subjects in the case of rotation and horizontal translation. 5. Joint space paths in both mastication and speech were found to be straight. The pattern was observed at normal and fast rates of speech and mastication and for loud speech as well. Straight line paths were also observed when subjects produced utterances that had both the syllabic structure and the intonation pattern of speech. The findings suggest that control may be organized in terms of an equilibrium jaw orientation and an equilibrium jaw position. 6. Departures from linearity were also observed. These were typically associated with differences during jaw closing in the end time of rotation and translation. Start time differences were not observed in jaw closing and the movement paths were typically linear within this region.

scholarly journals Feature Focus: Skyscrapers in a Microworld

2000 ◽  
Vol 122 (03) ◽  
pp. 64-67 ◽  
Author(s):  
Leo O’Connor ◽  
Harry Hutchinson
Keyword(s):  
Microelectromechanical Systems ◽  
Research Projects ◽  
X Ray ◽  
3D Cad ◽  
University Of Wisconsin ◽  
Manufacturing Methods ◽  
New Applications ◽  
The University ◽  
Selection Of ◽  
Advanced Research Projects Agency

This article reviews to enrich the variety of microelectromechanical systems (MEMS) to open new applications and markets. Established manufacturing methods for most MEMS were developed for electronics, and so the microcromachines turned out that way generally look like chips. The selection of materials is usually limited, and height, measured in microns, often remains in the single digits and rarely exceeds 20. Work at the University of Wisconsin in Madison is proceeding with a process that uses deep X-ray lithography. The technique is derived from an established micromanufacturing process known as LIGA, an acronym derived from the German terms for lithography, electroforming, and molding. LIGA, which has been around for a while, produces relatively tall micromachines by a method that radiates X-ray-sensitive materials to create molds. EFAB is being developed by USC’s Information Sciences Institute with funding from the Defense Advanced Research Projects Agency. To support commercialization of the process, the Institute has established the EFAB Consortium, which intends to give interested partners the option of acquiring prototype micro devices fabricated from their own 3D CAD designs.

scholarly journals The Missing Dimension in Developmental Biology Education

2008 ◽  
Vol 7 (1) ◽  
pp. 13-16
Author(s):  
Jeff Hardin
Keyword(s):  
Developmental Biology ◽  
Embryonic Development ◽  
Biology Education ◽  
Dynamic Events ◽  
University Of Colorado ◽  
University Of Wisconsin ◽  
Experience Teaching ◽  
Key Concepts ◽  
First Results ◽  
The University

Note from the Editor Points of View (POV) address issues faced by many people within the life science education community. CBE—Life Sciences Education (CBE-LSE) publishes the POV Feature to present two or more opinions published side-by-side on a common topic. We consider POVs to be “Op-Ed” pieces designed to stimulate thought and dialogue on significant educational issues. They are not meant to be exhaustive treatments of a subject. In this issue, we ask the question, “What are key concepts in developmental biology?” We present three POVs. The first is by CBE-LSE Editor-in-Chief, William Wood, and it is in part based on his experience teaching developmental biology to undergraduates at the University of Colorado, Boulder, including his collaborative experiments in the classroom with Jennifer Knight, the first results of which have been published in CBE-LSE ( Knight and Wood, 2005 ). The second, a partially tongue-in-cheek list of key concepts to convey to students about embryonic development, is by Scott Gilbert (Swarthmore College), author of the leading textbook worldwide for teaching developmental biology, Developmental Biology, 8th ed. (Sinauer Associates, Inc.). The third is by Jeff Hardin (University of Wisconsin–Madison), who has produced Web-based educational materials for teaching developmental biology that are used nationally and internationally for conveying dynamic events during early development (see the WWW feature in this issue by Stark for more details), and who deals with the vexing problem of trying to convey the essential four-dimensional nature of embryonic development to introductory students.

scholarly journals Simultaneous Multiwavelength Flare Observations of EV Lacertae

2021 ◽  
Vol 922 (1) ◽  
pp. 31
Author(s):  
Rishi R. Paudel ◽  
Thomas Barclay ◽  
Joshua E. Schlieder ◽  
Elisa V. Quintana ◽  
Emily A. Gilbert ◽  
...  
Keyword(s):  
Light Curve ◽  
Conclusive Evidence ◽  
M Dwarfs ◽  
Frequency Distributions ◽  
X Ray ◽  
First Results ◽  
Ev Lac ◽  
The University ◽  
First Ionization Potential ◽  
Flare Frequency

Abstract We present the first results of our ongoing project conducting simultaneous multiwavelength observations of flares on nearby active M dwarfs. We acquired data of the nearby dM3.5e star EV Lac using five different observatories: NASA’s Transiting Exoplanet Survey Satellite (TESS), NASA’s Neil Gehrels Swift Observatory (Swift), NASA’s Neutron Interior Composition Explorer (NICER), the University of Hawaii 2.2-meter telescope (UH88), and the Las Cumbres Observatory Global Telescope (LCOGT) Network. During the ∼25 days of TESS observations, we acquired three simultaneous UV/X-ray observations using Swift that total ∼18 ks, 21 simultaneous epochs totaling ∼98 ks of X-ray data using NICER, one observation (∼3 hr) with UH88, and one observation (∼3 hr) with LCOGT. We identified 56 flares in the TESS light curve with estimated energies in the range log E T (erg) = (30.5–33.2), nine flares in the Swift UVM2 light curve with estimated energies in the range log E UV (erg) = (29.3–31.1), 14 flares in the NICER light curve with estimated minimum energies in the range log E N (erg) = (30.5–32.3), and 1 flare in the LCOGT light curve with log E L (erg) = 31.6. We find that the flare frequency distributions (FFDs) of TESS and NICER flares have comparable slopes, β T = −0.67 ± 0.09 and β N = − 0.65 ± 0.19, and the FFD of UVOT flares has a shallower slope (β U = −0.38 ± 0.13). Furthermore, we do not find conclusive evidence for either the first ionization potential (FIP) or the inverse FIP effect during coronal flares on EV Lac.

scholarly journals Teaching Concepts Versus Facts in Developmental Biology

2008 ◽  
Vol 7 (1) ◽  
pp. 10-11 ◽  
Author(s):  
William B. Wood
Keyword(s):  
Developmental Biology ◽  
Embryonic Development ◽  
Dynamic Events ◽  
University Of Colorado ◽  
University Of Wisconsin ◽  
Experience Teaching ◽  
Education Community ◽  
Key Concepts ◽  
First Results ◽  
The University

Note from the Editor Points of View (POV) address issues faced by many people within the life science education community. CBE—Life Sciences Education (CBE-LSE) publishes the POV Feature to present two or more opinions published side-by-side on a common topic. We consider POVs to be “Op-Ed” pieces designed to stimulate thought and dialogue on significant educational issues. They are not meant to be exhaustive treatments of a subject. In this issue, we ask the question, “What are key concepts in developmental biology?” We present three POVs. The first is by CBE-LSE Editor-in-Chief, William Wood, and it is in part based on his experience teaching developmental biology to undergraduates at the University of Colorado, Boulder, including his collaborative experiments in the classroom with Jennifer Knight, the first results of which have been published in CBE-LSE ( Knight and Wood, 2005 ). The second, a partially tongue-in-cheek list of key concepts to convey to students about embryonic development, is by Scott Gilbert (Swarthmore College), author of the leading textbook worldwide for teaching developmental biology, Developmental Biology, 8th ed. (Sinauer Associates, Inc.). The third is by Jeff Hardin (University of Wisconsin–Madison), who has produced Web-based educational materials for teaching developmental biology that are used nationally and internationally for conveying dynamic events during early development (see the WWW feature in this issue by Stark for more details), and who deals with the vexing problem of trying to convey the essential four-dimensional nature of embryonic development to introductory students.

Some Biological Applications of High Voltage Electron Microscopy

1974 ◽  
Vol 32 ◽  
pp. 298-299
Author(s):  
Hans Ris
Keyword(s):  
High Voltage ◽  
Chromosome Structure ◽  
Nerve Fibers ◽  
Good Resolution ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
University Of Wisconsin ◽  
High Voltage Electron ◽  
One Year ◽  
The University

The High Voltage Electron Microscope Laboratory at the University of Wisconsin has been in operation a little over one year. I would like to give a progress report about our experience with this new technique. The achievement of good resolution with thick specimens has been mainly exploited so far. A cold stage which will allow us to look at frozen specimens and a hydration stage are now being installed in our microscope. This will soon make it possible to study undehydrated specimens, a particularly exciting application of the high voltage microscope.Some of the problems studied at the Madison facility are: Structure of kinetoplast and flagella in trypanosomes (J. Paulin, U. of Georgia); growth cones of nerve fibers (R. Hannah, U. of Georgia Medical School); spiny dendrites in cerebellum of mouse (Scott and Guillery, Anatomy, U. of Wis.); spindle of baker's yeast (Joan Peterson, Madison) spindle of Haemanthus (A. Bajer, U. of Oregon, Eugene) chromosome structure (Hans Ris, U. of Wisconsin, Madison). Dr. Paulin and Dr. Hanna are reporting their work separately at this meeting and I shall therefore not discuss it here.

Low temperature x-ray microanalysis of frozen-hydrated tobacco leaves

1984 ◽  
Vol 42 ◽  
pp. 284-285
Author(s):  
S. Edith Taylor ◽  
Patrick Echlin ◽  
May McKoon ◽  
Thomas L. Hayes
Keyword(s):  
Low Temperature ◽  
Lemna Minor ◽  
Root Tips ◽  
Tobacco Leaves ◽  
X Ray ◽  
Whole Cells ◽  
Carbon Coated ◽  
The Right ◽  
Beam Currents ◽  
The University

Low temperature x-ray microanalysis (LTXM) of solid biological materials has been documented for Lemna minor L. root tips. This discussion will be limited to a demonstration of LTXM for measuring relative elemental distributions of P,S,Cl and K species within whole cells of tobacco leaves.Mature Wisconsin-38 tobacco was grown in the greenhouse at the University of California, Berkeley and picked daily from the mid-stalk position (leaf #9). The tissue was excised from the right of the mid rib and rapidly frozen in liquid nitrogen slush. It was then placed into an Amray biochamber and maintained at 103K. Fracture faces of the tissue were prepared and carbon-coated in the biochamber. The prepared sample was transferred from the biochamber to the Amray 1000A SEM equipped with a cold stage to maintain low temperatures at 103K. Analyses were performed using a tungsten source with accelerating voltages of 17.5 to 20 KV and beam currents from 1-2nA.

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