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1.
Phys Rev Lett ; 132(15): 155101, 2024 Apr 12.
Article in English | MEDLINE | ID: mdl-38682996

ABSTRACT

The sheared-flow-stabilized Z pinch concept has been studied extensively and is able to produce fusion-relevant plasma parameters along with neutron production over several microseconds. We present here elevated electron temperature results spatially and temporally coincident with the plasma neutron source. An optical Thomson scattering apparatus designed for the FuZE device measures temperatures in the range of 1-3 keV on the axis of the device, 20 cm downstream of the nose cone. The 17-fiber system measures the radial profiles of the electron temperature. Scanning the laser time with respect to the neutron pulse time over a series of discharges allows the reconstruction of the T_{e} temporal response, confirming that the electron temperature peaks simultaneously with the neutron output, as well as the pinch current and inductive voltage generated within the plasma. Comparison to spectroscopic ion temperature measurements suggests a plasma in thermal equilibrium. The elevated T_{e} confirms the presence of a plasma assembled on axis, and indicates limited radiative losses, demonstrating a basis for scaling this device toward net gain fusion conditions.

2.
CBE Life Sci Educ ; 20(4): ar64, 2021 12.
Article in English | MEDLINE | ID: mdl-34714688

ABSTRACT

The Science Teaching Experience Program-Working in Science Education (STEP-WISE) provides teaching experience for postdoctoral scholars holding full-time research appointments. Through a combination of mentorship, deliberate practice, and feedback, the postdocs learn and apply inclusive, evidence-based pedagogies. STEP-WISE is integrated into postdocs' demanding schedules and is sustainable for institutions to run. Here, we assess the effectiveness of STEP-WISE. We used the Classroom Observation Protocol for Undergraduate STEM instruction to quantify instructor and student behaviors in 20 STEP-WISE class sessions from seven courses designed and taught by postdocs in the program. We found that all of the postdocs used student-centered teaching strategies. Also, using a design-based research framework, we studied the program to identify the salient components of its design. Four interconnected key elements contribute to the program's success: 1) two training sessions, 2) a precourse meeting with the mentor, 3) implementation of active-learning strategies with support, and 4) debriefing with the mentor after each class session. STEP-WISE is a replicable model to support postdocs seeking training and experience in evidence-based teaching practices geared to improving undergraduate education and transforming pedagogical practice. We conclude that high-impact teaching can be learned early in a career with streamlined training and intensive mentoring.


Subject(s)
Mentoring , Mentors , Humans , Learning , Research Personnel , Students
3.
Rev Sci Instrum ; 87(11): 11E521, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27910326

ABSTRACT

This paper provides an overview of the Thomson scattering diagnostic in use at General Fusion, including recent upgrades and upcoming plans. The plasma experiment under examination produces temperatures in the 50-500 eV range with density on the order of 1020 m-3. A four spatial point collection optics scheme has been implemented, with plans to expand to six spatial points. Recent changes to the optics of the laser beamline have reduced stray light. The system employs a frequency doubled Nd:YAG laser (532 nm), a grating spectrometer, and a photomultiplier array based detector.

4.
Rev Sci Instrum ; 87(11): 11E547, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27910649

ABSTRACT

The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD. Long-wavelength filters (1140 nm center, 80 nm bandwidth) have been added to the polychromators to improve capability to resolve non-Maxwellian distributions and to enable directed electron flow measurements. A supercontinuum (SC) pulsed white light source has replaced the tungsten halogen lamp previously used for spectral calibration of the polychromators. The SC source combines substantial brightness produced in nanosecond pulses with a spectrum that covers the entire range of the polychromators.

5.
Rev Sci Instrum ; 85(11): 11D808, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25430221

ABSTRACT

A new, high-repetition rate laser is in development for use on the Thomson scattering diagnostic on the Madison Symmetric Torus. The laser has been tested at a rate of 200 kHz in a pulse-burst operation, producing bursts of 5 pulses above 1.5 J each, while capable of bursts of 17 pulses at 100 kHz. A master oscillator-power amplifier architecture is used with a Nd:YVO4 oscillator, four Nd:YAG amplifiers, and a Nd:glass amplifier. A radial profile over the pulse sequence is measured by using a set of graphite apertures and an energy meter, showing a change in beam quality over a pulsing sequence.

6.
Phys Rev Lett ; 105(8): 085003, 2010 Aug 20.
Article in English | MEDLINE | ID: mdl-20868105

ABSTRACT

Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic E × B rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.

7.
J Air Waste Manag Assoc ; 50(11): 1897-903, 2000 Nov.
Article in English | MEDLINE | ID: mdl-11111334

ABSTRACT

It is important to characterize the chemical properties of particulate matter in order to understand how low doses, inhaled by a susceptible population, might cause human health effects. The formation of reactive oxygen species catalyzed by neutral, aqueous extracts of two ambient particulate samples, National Institute of Standards & Technology (NIST) Standard Reference Materials (SRM) 1648 and 1649, and two diesel particulate samples, NIST SRM 1650 and SRM 2975, were measured. The formation of reactive oxygen species was estimated by measuring the formation of malondialdehyde from 2-deoxyribose in the presence of ascorbic acid; H2O2 was not added to this assay. SRM 1649, ambient particulate matter collected from Washington, DC, generated the most malondialdehyde, while SRM 2975, diesel particulate matter collected from a forklift, yielded the least amount. Desferrioxamine inhibited the formation of malondialdehyde from the particulate samples providing additional data to support the observation that transition metals were involved in the generation of reactive oxygen species. Six transition metal sulfates (iron sulfate, copper sulfate, vanadyl sulfate, cobalt sulfate, nickel sulfate, and zinc sulfate) were assayed for their ability to generate reactive oxygen species under the same conditions used for the particulate samples in order to facilitate comparisons between particles and these transition metals. The concentration of transition metals was measured in aqueous extracts of these particulate samples using ion-coupled plasma mass spectrometry (ICP-MS) analysis. There was qualitative agreement between the concentrations of Fe, Cu, and V and the amount of malondialdehyde produced from extracts of these particulate samples. These data suggest that transition metals can be dissolved from particles in neutral, aqueous solutions and that these metals are capable of catalyzing the formation of reactive oxygen species.


Subject(s)
Air Pollutants, Occupational/chemistry , Reactive Oxygen Species , Vehicle Emissions/analysis , Air Pollutants, Occupational/toxicity , Catalysis , Malondialdehyde/analysis , Mass Spectrometry , Vehicle Emissions/toxicity
8.
Am J Psychother ; 49(2): 282-91, 1995.
Article in English | MEDLINE | ID: mdl-7677206

ABSTRACT

EMDR resulted in the rapid relief of symptoms of posttraumatic stress disorder in refractory traumatic imagery in a Vietnam veteran. The results were maintained at nine-month follow-up. EMDR appears to be a viable technique in anecdotal reports but the limitations of a single-case study and the lack of adequate large controlled studies prevent generalization beyond a case-by-case assessment. Despite controversial reports, it appears that more rigorous evaluation of EMDR needs to be done to document the factors that operate in the use of EMDR.


Subject(s)
Combat Disorders/therapy , Desensitization, Psychologic/methods , Eye Movements , Grief , Veterans/psychology , Combat Disorders/psychology , Humans , Male , Mental Recall , Middle Aged , Vietnam
9.
Prim Care ; 20(2): 447-58, 1993 Jun.
Article in English | MEDLINE | ID: mdl-8356163

ABSTRACT

Sadistic ritual abuse, including satanic cult abuse, is emerging as a syndrome among people with severe dissociative disorders, including multiple personality disorder. This article discusses the essential features that compose the clinical picture of sadistic ritual abuse in adults, adolescents, and children. Particular attention is paid to the differences between adolescents who may have been victimized by adults in sadistic and ritualized ways and disenfranchised "teenage dabblers" who may temporarily adopt a ritualized lifestyle as a way of expressing or acting out. The article also covers guidelines for appropriate medical, pharmacologic, and referral interventions. The controversy surrounding sadistic ritual abuse is discussed thoroughly, and primary care physicians are advised of the current status of understanding and validation in this area.


Subject(s)
Ceremonial Behavior , Child Abuse/diagnosis , Child Abuse/therapy , Family Practice/methods , Occultism , Sadism , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/therapy , Adolescent , Adult , Child , Child Abuse/complications , Child Abuse/psychology , Humans , Life Style , Psychotherapy , Referral and Consultation , Stress Disorders, Post-Traumatic/complications , Stress Disorders, Post-Traumatic/psychology
10.
Radiology ; 185(3): 904-7, 1992 Dec.
Article in English | MEDLINE | ID: mdl-1438784

ABSTRACT

The authors performed topographic correlation of dosimetric measurements with contrast medium-enhanced magnetic resonance (MR) imaging signal aberration in two cases of radiation optic neuropathy. The region of pathologic contrast enhancement in the optic nerve and chiasm had received 55-62 Gy, which supports the theory that the risk of injury to the optic nerve and chiasm increases steeply with radiation doses above the tolerance level of 50-55 Gy.


Subject(s)
Magnetic Resonance Imaging , Optic Nerve Diseases/diagnosis , Optic Nerve Diseases/etiology , Radiation Injuries/diagnosis , Radiotherapy/adverse effects , Female , Humans , Male , Middle Aged , Optic Chiasm/pathology , Optic Chiasm/radiation effects , Optic Nerve/pathology , Optic Nerve/radiation effects , Radiation Dosage
11.
Mutat Res ; 282(2): 89-92, 1992 Jun.
Article in English | MEDLINE | ID: mdl-1377356

ABSTRACT

In order to determine the efficiency of organic solvent extractions of fresh diesel-engine exhaust particles a series of Soxhlet extractions were set up using single and sequential extractions of fresh diesel particles with solvents of increasing polarities. Single extractions were carried out with methylene chloride, methanol, acetone and acetonitrile. A single filter was sequentially extracted with methylene chloride followed by methanol, acetone and acetonitrile. Methylene chloride extracted the most mutagenicity relative to the other three solvents. In addition, methylene chloride extracted 97% of the total extracted mutagenicity from a sequential series of extractions. Therefore, we conclude that of the solvents tested methylene chloride extracts the highest proportion of mutagens from fresh diesel exhaust and little mutagenicity is lost using methylene chloride as the only extraction solvent.


Subject(s)
Mutagens/isolation & purification , Vehicle Emissions/analysis , Acetone/chemistry , Acetonitriles/chemistry , Methanol/chemistry , Methylene Chloride/chemistry , Mutagens/chemistry , Solubility , Solvents
12.
Radiology ; 182(2): 477-81, 1992 Feb.
Article in English | MEDLINE | ID: mdl-1732967

ABSTRACT

Congenital absence of one or both internal carotid arteries (ICAs) has a high association with circle of Willis aneurysm formation. Since the carotid canals in the skull base form secondary to the presence of the embryonic ICA, absence or hypoplasia of a carotid canal on a computed tomographic (CT) scan through the skull base should suggest a congenital ICA abnormality and prompt a search for associated intracranial vascular abnormalities. Of four patients with carotid canal underdevelopment evident at CT, two had associated circle of Willis aneurysms and a third had an extensive skull base rete mirabile supplying an abnormal tangle of vessels in the basal cisterns. Only two patients (one with an aneurysm, one with the skull base rete mirabile) presented with subarachnoid hemorrhage. One patient presented with monocular decreasing vision due to an enlarging aneurysm, and one patient was essentially asymptomatic. If asymmetry or absence of the carotid canals is evident on CT scans of the head, further evaluation to rule out a potentially life-threatening intracranial vascular abnormality such as those found in these patients should be seriously considered, even in a young or asymptomatic patient.


Subject(s)
Carotid Artery, Internal/abnormalities , Skull/abnormalities , Tomography, X-Ray Computed , Aged , Carotid Artery, Internal/diagnostic imaging , Cerebral Angiography , Child, Preschool , Congenital Abnormalities/diagnostic imaging , Female , Humans , Middle Aged , Skull/diagnostic imaging
14.
Chem Biol Interact ; 77(3): 291-302, 1991.
Article in English | MEDLINE | ID: mdl-2009575

ABSTRACT

The mutagenicities of the five possible isomers of bromomethylfluoranthene, chloromethylfluoranthene, and hydroxymethylfluoranthene were determined in the Ames assay using strains TA100 and TA98 without the addition of rat-liver S9 tissue extract. The mutagenicities of the bromomethyl and chloromethylfluoranthenes ranged from 25 to 6000 rev./nmol. The most mutagenic compound was 8-chloromethylfluoranthene in strain TA98 (6000 rev./nmol). The reactivities of the bromomethylfluoranthenes and the chloromethylfluoranthenes were estimated from electronic structure calculations using the MNDO and the PM3 semi-empirical methods. The bromomethylfluoranthenes showed the smallest differences between the heats of formation of the carbocations and the heats of formation of the parent bromomethyl derivatives. Therefore, the bromomethylfluoranthenes were estimated to be the most reactive of the halomethylfluoranthenes studied. The compound that showed the largest change in heat of formation (the most stable halomethylfluoranthene) going from the halomethylfluoranthene to the carbocation was 2-chloromethylfluoranthene. However, neither the most reactive nor the most stable halomethylfluoranthenes were the most mutagenic in either strain of bacteria. These results are interpreted to suggest that the reactivity of the parent halomethylfluoranthene is not a critical factor in the mechanism by which these compounds are mutagenic, but some other factor, perhaps intercalation, must be a critical step in the mechanism of mutagenesis of these compounds.


Subject(s)
Fluorenes/toxicity , Hydrocarbons, Brominated/toxicity , Hydrocarbons, Chlorinated/toxicity , Methanol/analogs & derivatives , Mutagenicity Tests , Acetone , Dimethyl Sulfoxide , Fluorenes/chemistry , Hydrocarbons, Brominated/chemistry , Hydrocarbons, Chlorinated/chemistry , Methanol/chemistry , Methanol/toxicity , Molecular Structure , Solvents , Thermodynamics
15.
Child Abuse Negl ; 15(3): 181-9, 1991.
Article in English | MEDLINE | ID: mdl-2043970

ABSTRACT

Thirty-seven adult dissociative disorder patients who reported ritual abuse in childhood by satanic cults are described. Patients came from a variety of separate clinical settings and geographical locations and reported a number of similar abuses. The most frequently reported types of ritual abuse are outlined, and a clinical syndrome is presented which includes dissociative states with satanic overtones, severe post-traumatic stress disorder, survivor guilt, bizarre self abuse, unusual fears, sexualization of sadistic impulses, indoctrinated beliefs, and substance abuse. Questions relating to issues of reliability, credibility and verifiability are addressed in depth, and the findings and implications are discussed.


Subject(s)
Ceremonial Behavior , Child Abuse, Sexual/psychology , Dissociative Disorders/psychology , Magic/psychology , Personality Development , Sadism/psychology , Abreaction , Adolescent , Adult , Child , Child Abuse, Sexual/diagnosis , Child Abuse, Sexual/therapy , Diagnosis, Differential , Dissociative Disorders/diagnosis , Dissociative Disorders/therapy , Dissociative Identity Disorder/diagnosis , Dissociative Identity Disorder/psychology , Dissociative Identity Disorder/therapy , Female , Hospitalization , Humans , Hypnosis , Male , Middle Aged , Psychotherapy/methods , Religion and Psychology , Syndrome
18.
Int J Biol Markers ; 3(1): 1-9, 1988.
Article in English | MEDLINE | ID: mdl-3249042

ABSTRACT

In patients or mice with cancer the pharmacokinetic behavior of radioiodinated and radiometal chelated antibodies has been observed to be different. Rapid clearance from the tissues and excretion into the urine can occur after injection of radioiodinated antibodies. These observations have been interpreted to reflect in vivo dehalogenation of the antibody. This publication describes a variety of other mechanisms that can underlie these phenomena. These mechanisms include receptor uptake and catabolism of antibody and instability of the labeled antibody due to the labeling conditions. Specifically, the relative masses of chloramine-T and antibody in the iodination reaction mixture, the level of iodination of the antibody, and the amount of antibody administered to the recipient are all factors which can influence the clearance of radioiodinated antibody from the recipient. The final determinant for the different behavior of radioiodinated and In-111 metal chelated antibody relate to the different biologic pathways of indium when compared to iodine.


Subject(s)
Antibodies, Monoclonal/urine , Iodine Radioisotopes/urine , Isotope Labeling/methods , Tosyl Compounds , Animals , Antibodies, Monoclonal/administration & dosage , Chloramines/pharmacology , Chromatography, High Pressure Liquid , Electrophoresis, Cellulose Acetate , Humans , Lymphoma/urine , Mice , Tissue Distribution
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