ABSTRACT
The precise value of the mean neutron lifetime, τn, plays an important role in nuclear and particle physics and cosmology. It is used to predict the ratio of protons to helium atoms in the primordial universe and to search for physics beyond the Standard Model of particle physics. We eliminated loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls. As a result of this approach and the use of an in situ neutron detector, the lifetime reported here [877.7 ± 0.7 (stat) +0.4/-0.2 (sys) seconds] does not require corrections larger than the quoted uncertainties.
ABSTRACT
In this paper, we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold neutrons (UCN), which provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. An active detector that can be lowered into the trap has been used to measure the neutron distribution as a function of height and measure the influence of marginally trapped UCN on the neutron lifetime measurement. In addition, measurements have demonstrated phase-space evolution and its effect on the lifetime measurement.
ABSTRACT
INTRODUCTION: Improvements in the imaging capabilities of angiographic C-arm computed tomography (CT) using flat detector angiographic (FD-CT) systems now provide a means for the in vivo visualization of devices used for the treatment of intracranial aneurysms. One such device, the WEB embolization device, is made of a braided mesh of nitinol wires, the size of which are near to the limits of visualization using conventional x-ray fluoroscopy. Our hypothesis was that the imaging of these implants C-arm CT would provide useful information regarding their positioning and deployment. METHODS: In five New Zealand white rabbits elastase induced aneurysms were created and subsequently treated using a WEB. Imaging was performed using digital subtraction angiography (DSA), X-ray imaging and two different Angiographic C-arm CT protocols. The images were evaluated by two neuroradiologists using an evaluation scale. RESULTS: The mesh of the WEB was barely visible on the DSA or x-ray fluoroscopy images. Volume rendering technique (VRT) reconstruction and multiplanar reconstruction (MPR) of images done using the C-arm CT protocols clearly delineated the shape and structure of the device. Contrast-enhanced MPR and VRT reconstructions allowed assessment of the status of blood flow in the aneurysms. Beam hardening artifacts caused by platinum markers on the WEB were present. CONCLUSION: In vivo C-arm CT imaging of the WEB is feasible and allows precise determination of the position and deployment status of the device. On contrast-enhanced images the occlusion status of aneurysms and the positioning of the WEB in relationship to the parent artery can be evaluated. C-arm-CT may serve as a minimal-invasive follow-up imaging modality.
Subject(s)
Cerebral Angiography/methods , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/therapy , Mechanical Thrombolysis/instrumentation , Radiography, Interventional/methods , Surgical Mesh , Tomography, X-Ray Computed/methods , Animals , Equipment Failure Analysis , Intracranial Aneurysm/chemically induced , Mechanical Thrombolysis/methods , Pancreatic Elastase , Prosthesis Design , Rabbits , Treatment OutcomeABSTRACT
The strip patch test is recommended whenever a patch test is presumed to be false negative. The aim of this technique is to increase skin sensitivity to test substances by removing the upper layers of the stratum corneum prior to patch testing. We report on a 57-year-old former heavy-current electrical worker, who suffered from hyperkeratotic fissured hand eczema. Sensitization to nickel sulphate was demonstrated in both 2001 and 2009 with strip patch testing even though conventional patch testing was negative. To our knowledge, this is the first description of an allergy to nickel with a pension entitlement according to no. 5101 of the German ordinance on industrial disease based solely on positive strip patch tests.
Subject(s)
Dermatitis, Allergic Contact/diagnosis , Dermatitis, Occupational/diagnosis , Irritants , Nickel/adverse effects , Patch Tests/methods , Expert Testimony/legislation & jurisprudence , False Negative Reactions , Germany , Humans , Male , Middle Aged , Workers' Compensation/legislation & jurisprudenceABSTRACT
OBJECTIVE: To evaluate the number of lysosomes in glandular epithelia of the endometrioma capsule and endometrium from patients with or without endometriosis using a histochemical method (acidic phosphate determination) under light microscopy. METHOD: We studied 31 selected patients with similar clinical features, except for the occurrence of menorrhagia enhanced in patients with endometriosis. All patients were submitted to video laparoscopic procedures and endometrial biopsies through hysteroscopy during the secretory phase. After surgery, the patients were divided into two groups for hysteroscopic data: GI--without endometriosis (control, n = 16) and GII--with endometriosis (n = 15). In GII, the lysosomes of the endometrioma were also counted (GIIa). RESULTS: The GI sample was comprised only of endometrial biopsies. We found that the number of lysosomes in the topic endometrial tissue of patients with endometriosis was significantly larger than the number in endometrioma. Also, there were more lysosomes in the endometrium of patients with endometriosis than in endometrioma-bearing patients. CONCLUSION: Our data suggest that variations in the number of lysosomes may underlie the pathogenesis of endometriosis.
Subject(s)
Endometriosis/pathology , Endometrium/pathology , Lysosomes/pathology , Adult , Biopsy , Case-Control Studies , Cell Count , Endometriosis/surgery , Female , Humans , Hysteroscopy , Luteal Phase/physiology , Prospective StudiesABSTRACT
The synthesis of the enantiomeric 14-methyl-1-octadecenes in >99% EE is described. Enantiomeric 2-methyl-1-hexanols were intermediates in the synthesis. The 1-alkene had been previously identified as the sex pheromone of the peach leafminer moth. Several closely related structures that have δ12 unsaturation are also described.
