Apparatus for precision focussing and positioning of a beam waist on a target

The invention relates to optical focussing apparatus and, more particularly, to optical apparatus for focussing a highly collimated Gaussian beam which provides independent and fine control over the focus waist diameter, the focus position both along the beam axis and transverse to the beam, and the focus angle. A beam focussing and positioning apparatus provides focussing and positioning for the waist of a waisted beam at a desired location on a target such as an optical fiber. The apparatus includes a first lens, having a focal plane f sub 1, disposed in the path of an incoming beam and a second lens, having a focal plane f sub 2 and being spaced downstream from the first lens by a distance at least equal to f sub 1 + 10 f sub 2, which cooperates with the first lens to focus the waist of the beam on the target. A rotatable optical device, disposed upstream of the first lens, adjusts the angular orientation of the beam waist. The transverse position of the first lens relative to the axis of the beam is varied to control the transverse position of the beam waist relative to the target (a fiber optic as shown) while the relative axial positions of the lenses are varied to control the diameter of the beam waist and to control the axial position of the beam waist. Mechanical controllers C sub 1, C sub 2, C sub 3, C sub 4, and C sub 5 control the elements of the optical system. How seven adjustments can be made to correctly couple a laser beam into an optical fiber is illustrated. Prior art systems employing optical techniques to couple a laser beam into an optical fiber or other target simply do not provide the seven necessary adjustments. The closest known prior art, a Newport coupler, provides only two of the seven required adjustments

Output optics for laser velocimeters

Space savings are effected in the optical output system of a laser velocimeter. The output system is comprised of pairs of optical fibers having output ends from which a beam of laser light emerges, a transfer lens for each light beam, and at least one final (LV) lens for receiving the light passing through the transfer lenses and for focussing that light at a common crossing point or area. In order to closely couple the transfer lenses to the final lens, each transfer lens is positioned relative to the final lens receiving light therefrom such that the output waist of the corresponding beam received by the final lens from the transfer lens is a virtual waist located before the transfer lens

Survival of verapamil-poisoned rats treated with triiodothyronine.

Life-threatening toxicity due to calcium channel blocker ingestion is commonly encountered by emergency medicine physicians and toxicologists. Despite a vast array of research on its treatment, results have proven inconsistent. The goal of this study is to evaluate potential vasopressor effects of triiodothyronine (T3) in rats poisoned with verapamil. Following anesthesia and intubation, ten Sprague-Dawley rats were given intravenous verapamil infusion of 10 mg/kg/h. This dose was titrated until a mean arterial pressure (MAP) of 50-55 mmHg was achieved and maintained for a period of at least 5 min. The verapamil infusion was then maintained at that rate. Five rats were randomized to receive a T3 bolus of 0.4 mcg/kg preceding an infusion of 1.5 mcg/kg/day which was doubled every 2 min until any of the following endpoints: systolic blood pressure of 100 mmHg, an elapsed time of 60 min, or death. The other five received an equal volume of normal saline solution. The primary outcome measure was survival with secondary outcomes of MAP and heart rate. The T3 group did have a slightly longer, yet not statistically significant, average time to cessation of electrical activity-30.0 +/- 14.4 min versus 23.8 +/- 9.5 min in the placebo group. Average MAP decreased nearly identically in the two groups. Heart rates were not reliable indicators of toxicity in this rat model as there was little decrease until immediately prior to death in most animals. Despite significant variability in toxicity among individual animals, no statistically significant difference in survival time, heart rate, or MAP was found between groups treated with T3 and those receiving saline

Hypothermia: an unusual indication for gastric lavage.

BACKGROUND: Previous reports suggest that gastric lavage holds many risks and is not routinely indicated for decontamination of the overdose patient. OBJECTIVE: To present a case of overdose with concurrent accidental hypothermia where gastric decontamination was utilized. CASE REPORT: A 50-year-old hypothermic, comatose patient was transported to the Emergency Department with a concurrent, massive medication ingestion diagnosed incidentally on a routine abdominal computed tomography scan. Both active and passive rewarming measures, in conjunction with gastric lavage and retrieval of multiple pill fragments, were performed, and the patient survived to hospital discharge without sequelae. Interestingly, the patient admitted to an intentional ingestion of both labetalol and lorazepam. CONCLUSION: Due to hypothermia-mediated changes in metabolism, including gastric atony and decreased hepatic metabolism, gastric lavage may provide additional benefit in the management of severely hypothermic patients with potentially lethal, massive pill ingestions

Resonant and Non-Resonant Effects in Photon-Technipion Production at Lepton Colliders

Lepton collider experiments can search for light technipions in final states made striking by the presence of an energetic photon: e+e- \to \photon\technipion. To date, searches have focused on either production through anomalous coupling of the technipions to electroweak gauge bosons or on production through a technivector meson (\technirho, \techniomega) resonance. This paper creates a combined framework in which both contributions are included. This will allow stronger and more accurate limits on technipion production to be set using existing data from LEP or future data from a higher-energy linear collider. We provide explicit formulas and sample calculations (analytic and Pythia) in the framework of the Technicolor Straw Man Model, a model that includes light technihadrons.Comment: 11 pages, including title page, 3 figures; version 2: references adde

Quantitative Three-dimensional Assessment of Knee Joint Space Width from Weight-bearing CT.

Background Imaging of structural disease in osteoarthritis has traditionally relied on MRI and radiography. Joint space mapping (JSM) can be used to quantitatively map joint space width (JSW) in three dimensions from CT images. Purpose To demonstrate the reproducibility, repeatability, and feasibility of JSM of the knee using weight-bearing CT images. Materials and Methods Two convenience samples of weight-bearing CT images of left and right knees with radiographic Kellgren-Lawrence grades (KLGs) less than or equal to 2 were acquired from 2014 to 2018 and were analyzed retrospectively with JSM to deliver three-dimensional JSW maps. For reproducibility, images of three sets of knees were used for novice training, and then the JSM output was compared against an expert's assessment. JSM was also performed on 2-week follow-up images in the second cohort, yielding three-dimensional JSW difference maps for repeatability. Statistical parametric mapping was performed on all knee imaging data (KLG, 0-4) to show the feasibility of a surface-based analysis in three dimensions. Results Reproducibility (in 20 individuals; mean age, 58 years ± 7 [standard deviation]; mean body mass index, 28 kg/m2 ± 6; 14 women) and repeatability (in nine individuals; mean age, 53 years ± 6; mean body mass index, 26 kg/m2 ± 4; seven women) reached their lowest performance at a smallest detectable difference less than ±0.1 mm in the central medial tibiofemoral joint space for individuals without radiographically demonstrated disease. The average root mean square coefficient of variation was less than 5% across all groups. Statistical parametric mapping (33 individuals; mean age, 57 years ± 7; mean body mass index, 27 kg/m2 ± 6; 23 women) showed that the central-to-posterior medial joint space was significantly narrower by 0.5 mm for each incremental increase in the KLG (threshold P < .05). One knee (KLG, 2) demonstrated a baseline versus 24-month change in its three-dimensional JSW distribution that was beyond the smallest detectable difference across the lateral joint space. Conclusion Joint space mapping of the knee using weight-bearing CT images is feasible, demonstrating a relationship between the three-dimensional joint space width distribution and structural joint disease. It is reliably learned by novice users, can be personalized for disease phenotypes, and can be used to achieve a smallest detectable difference that is at least 50% smaller than that reported to be achieved at the highest performance level in radiography. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Roemer in this issue

Object Relations in the Museum: A Psychosocial Perspective

This article theorises museum engagement from a psychosocial perspective. With the aid of selected concepts from object relations theory, it explains how the museum visitor can establish a personal relation to museum objects, making use of them as an ‘aesthetic third’ to symbolise experience. Since such objects are at the same time cultural resources, interacting with them helps the individual to feel part of a shared culture. The article elaborates an example drawn from a research project that aimed to make museum collections available to people with physical and mental health problems. It draws on the work of the British psychoanalysts Donald Winnicott and Wilfred Bion to explain the salience of the concepts of object use, potential space, containment and reverie within a museum context. It also refers to the work of the contemporary psychoanalyst Christopher Bollas on how objects can become evocative for individuals both by virtue of their intrinsic qualities and by the way they are used to express personal idiom

Following Tetraploidy in Maize, a Short Deletion Mechanism Removed Genes Preferentially from One of the Two Homeologs

Following genome duplication and selfish DNA expansion, maize used a heretofore unknown mechanism to shed redundant genes and functionless DNA with bias toward one of the parental genomes