Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Rev Sci Instrum ; 91(7): 073301, 2020 Jul 01.
Article in English | MEDLINE | ID: mdl-32752855

ABSTRACT

Transverse 2D phase space distributions of a 2.1 MeV, 5 mA H- beam are measured at the Proton Improvement Plan II Injector Test accelerator at Fermilab with an Allison scanner. This paper describes the design, calibration, and performance of the scanner along with the main results from beam measurements. Analyses of the recorded phase portraits are performed primarily in action-phase coordinates. The stability of the action under linear optics makes it easier to compare measurements taken under different beamline conditions. The amplitude of a single measured point ("pixel") is proportional to the phase density in the corresponding portion of the beam. When the Twiss parameters are calculated using only the high-phase density part of the beam, the pixel amplitude in the beam core is found to be decreasing approximately exponentially with action and to be phase-independent. Outside of the core, the amplitudes decrease with action at a slower rate than in the core. This "tail" comprises 10%-30% of the beam, with 0.1% of the total measured intensity extending beyond action 10-20 times larger than the rms emittance. The transition from the core to the tail is accompanied by the appearance of two "branches" that are separated in phase and extend beyond the core. A set of selected measurements shows that there is no measurable emittance dilution along the beamline; the beam parameters are practically constant over a 0.5 ms pulse; and scraping in various parts of the beamline is an effective way to decrease the transverse tails by removing the branches.

2.
J Physiol Pharmacol ; 65(1): 107-15, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24622835

ABSTRACT

Potential effects of prenatal administration of acrylamide (ACR) on postnatal development of the small intestine were not examined experimentally yet. The aim of this study was to establish changes of morphological parameters of the small intestine damaged by prenatal action of ACR in guinea pigs. The 3 mg/kg body weight of ACR was given in drinking water every day during the last 35 days of the pregnancy in guinea pigs. The histomorphometry of the duodenum and jejunum was determined. Immunohistochemical staining with anti cadherin antibody was performed. Maternal treatment with ACR led to the decrease of the expression of cadherin in the epithelium. Maternal ACR treatment increased the number of total, divided and inactive crypt, and the number of damaged villi in the duodenum and jejunum of newborn guinea pigs. The thickness of myenteron and submucosa, mucosa fractal dimension and the depth of crypts in the duodenum were increased by ACR. Additionally, in offspring born by mothers administered with ACR the decrease of villi epithelium thickness and active crypt number was observed. Moreover, ACR decreased goblet cells and inact villi number in the duodenum, mucosa thickness and crypts width in the jejunum. Intestine absorptive surface was affected by ACR in the jejunum as well. Results of measurements showed that maternal ACR treatment had negative influence on small intestine histomorphometry. ACR acting prenatally influenced small intestine nervous plexuses that became enlarged by 2.5 times compared with the control group. In conclusion, our results showed the negative impact of maternal ACR treatment on histological structure, integrity and innervation of small intestine wall as well as on absorptive function of small intestine mucosa.


Subject(s)
Acrylamide/toxicity , Duodenum/drug effects , Jejunum/drug effects , Prenatal Exposure Delayed Effects , Animals , Apoptosis/drug effects , Collagen Type I/metabolism , Collagen Type III/metabolism , Duodenum/metabolism , Duodenum/pathology , Female , Guinea Pigs , Intestinal Absorption/drug effects , Intestinal Mucosa/drug effects , Intestinal Mucosa/metabolism , Intestinal Mucosa/pathology , Jejunum/metabolism , Jejunum/pathology , Male , Maternal-Fetal Exchange , Pregnancy
3.
Phys Rev Lett ; 98(6): 064801, 2007 Feb 09.
Article in English | MEDLINE | ID: mdl-17358950

ABSTRACT

During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dE_{e}/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

4.
Clin Chem Lab Med ; 38(6): 513-7, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10987199

ABSTRACT

The determination of plasma methoxyamines is the most informative parameter for the diagnosis of pheochromocytoma. Very good sensitivity and specificity are necessary for this. The measurement of deconjugated (free plus sulfate-conjugated) metanephrines is more useful. Concentrations are 10-fold higher than free metanephrine concentrations. The methodology generally uses a column purification and high performance liquid chromatography with electrochemical detection. We have tested six commercial columns used for the purification step. We chose a rapid and reliable method with a mixture of strong cation-exchange and strong anion-exchange groups bonded onto a silica column. This protocol has been validated with samples of plasma from normal subjects, healthy elderly people, renal failure patients and patients with pheochromocytoma.


Subject(s)
Chromatography, High Pressure Liquid/methods , Metanephrine/blood , Pheochromocytoma/blood , Humans , Pheochromocytoma/diagnosis , Sensitivity and Specificity
SELECTION OF CITATIONS
SEARCH DETAIL
...