scholarly journals A Moving Liver Phantom in An Anthropomorphic Thorax for SPECT MP Imaging

2021 ◽  
Author(s):  
Sotiris Panagi ◽  
Anastasia Hadjiconstanti ◽  
George Charitou ◽  
Demetris Kaolis ◽  
Ioannis Petrou ◽  
...  
Keyword(s):  
Respiratory Motion ◽  
Time Interval ◽  
Myocardial Wall ◽  
Liver Activity ◽  
Cardiac Phantom ◽  
Activity Ratios ◽  
First Time ◽  
Respiratory Phases ◽  
Liver Phantom ◽  
Ct Slices

Abstract Cranio-caudal respiratory motion and liver activity cause a variety of complex myocardial perfusion (MP) artifacts, especially in the inferior myocardial wall, that may also mask cardiac defects. To assess and characterize such artifacts, an anthropomorphic thorax with moving thoracic phantoms can be utilized in SPECT MP imaging. In this study, a liver phantom was developed, and anatomically added into an anthropomorphic phantom, that encloses an ECG beating cardiac phantom and breathing lungs phantom. A cranio-caudal respiratory motion was also developed for the liver phantom and it was synchronized with the corresponding ones of the cardiac and lungs phantoms. This continuous motion could also be further divided into dynamic respiratory phases, from end-exhalation to end-inspiration, to perform SPECT acquisitions in different respiratory phases. The motion parameters, displacements and volumes, were validated by the acquired CT slices, the OsiriX and Vitrea software. Sample SPECT/16-slice-CT myocardial MP acquisitions were also performed and compared to the literature. The cardiac, lungs and liver phantoms can precisely perform, in time interval of 0.1 sec, physiological thoracic motions within an anthropomorphic thorax. This dynamic phantom assembly can be utilized for SPECT MP supine and, for first time, prone imaging to access and characterize artifacts due to different cranio-caudal respiratory amplitudes and cardiac-liver activity ratios.

scholarly journals A moving liver phantom in an anthropomorphic thorax for SPECT MP imaging

2022 ◽  
Author(s):  
S. Panagi ◽  
Α. Hadjiconstanti ◽  
G. Charitou ◽  
D. Kaolis ◽  
I. Petrou ◽  
...  
Keyword(s):  
Motion Correction ◽  
Respiratory Motion ◽  
Clinical Environment ◽  
Myocardial Wall ◽  
Liver Activity ◽  
Cardiac Phantom ◽  
The Impact ◽  
First Time ◽  
Respiratory Phases ◽  
Liver Phantom

AbstractCranio-caudal respiratory motion and liver activity cause a variety of complex myocardial perfusion (MP) artifacts, especially in the inferior myocardial wall, that may also mask cardiac defects. To assess and characterise such artifacts, an anthropomorphic thorax with moving thoracic phantoms can be utilised in SPECT MP imaging. In this study, a liver phantom was developed and anatomically added into an anthropomorphic phantom that also encloses an ECG beating cardiac phantom and breathing lungs’ phantom. A cranio-caudal respiratory motion was also developed for the liver phantom and it was synchronised with the corresponding ones of the other thoracic phantoms. This continuous motion was further divided into isochronous dynamic respiratory phases, from end-exhalation to end-inspiration, to perform SPECT acquisitions in different respiratory phases. The new motions’ parameters and settings were measured by mechanical means and also validated in a clinical environment by acquiring CT images and by using two imaging software packages. To demonstrate the new imaging capabilities of the phantom assembly, SPECT/CT MP acquisitions were performed and compared to previous phantom and patients studies. All thoracic phantoms can precisely perform physiological motions within the anthropomorphic thorax. The new capabilities of the phantom assembly allow to perform SPECT/CT MP acquisitions for different cardiac-liver activity ratios and cardiac-liver proximities in supine and, for first time, in prone position. Thus, MP artifacts can be characterised and motion correction can be performed due to these new capabilities. The impact of artifacts and motion correction on defect detection can be also investigated.

scholarly journals Period-Life of a Branching Process with Migration and Continuous Time

Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 868
Author(s):  
Khrystyna Prysyazhnyk ◽  
Iryna Bazylevych ◽  
Ludmila Mitkova ◽  
Iryna Ivanochko
Keyword(s):  
Random Process ◽  
Generating Function ◽  
Continuous Time ◽  
Branching Process ◽  
Probability Generating Function ◽  
Time Interval ◽  
The Moment ◽  
First Time ◽  
Critical Branching Process ◽  
Number Of Particles

The homogeneous branching process with migration and continuous time is considered. We investigated the distribution of the period-life τ, i.e., the length of the time interval between the moment when the process is initiated by a positive number of particles and the moment when there are no individuals in the population for the first time. The probability generating function of the random process, which describes the behavior of the process within the period-life, was obtained. The boundary theorem for the period-life of the subcritical or critical branching process with migration was found.

scholarly journals NUTRITION OF THE HOST AND NATURAL RESISTANCE TO INFECTION

1949 ◽  
Vol 89 (5) ◽  
pp. 529-539 ◽  
Author(s):  
Howard A. Schneider
Keyword(s):  
Inbred Mouse ◽  
Natural Resistance ◽  
Single Infection ◽  
Mouse Strains ◽  
Time Interval ◽  
Special Cases ◽  
Resistance To Infection ◽  
Relationship Of ◽  
First Time ◽  
The Relationship

The double strain inoculation (DSI) method of testing for natural resistance to infection has been examined in the instance of mouse salmonellosis. The DSI method has been found capable of detecting differences in natural resistance due to genetic as well as nutritional causes. A difference in response to Salmonella infection was found for the first time between the two "susceptible" inbred mouse strains, BSVR and BSVS. Whereas BSVS mice for the most part survived an intraperitoneal injection of 103 "avirulent" S. typhimurium, BSVR mice all succumbed. The relationship of the DSI test to the usual single infection test has been discussed and it is suggested that such single infection tests are special cases of the DSI test, since they involve a heterogeneous bacterial population which can be considered as a mixture of cultures of differing virulence and in which, by a single injection, the usual time interval between the two injections of the DSI method has been reduced to 0.

scholarly journals Glucocorticoids do not influence the effect of radioiodine therapy in Graves’ disease

2005 ◽  
Vol 153 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Berit E Jensen ◽  
Steen J Bonnema ◽  
Laszlo Hegedüs
Keyword(s):  
Thyroid Peroxidase ◽  
Graves Disease ◽  
Time Interval ◽  
Cure Rate ◽  
Radiation Induced ◽  
Eye Symptoms ◽  
High Concentrations ◽  
Group 2 ◽  
First Time ◽  
Group 1

Objective: We evaluated, in a retrospective study, whether glucocorticoids given in order to avoid initiation or aggravation of ophthalmopathy during radioiodine (131I) therapy have an inadvertent effect on the final thyroid function. Methods: Consecutive patients with Graves’ disease (median age 50 years, range 21–82 years) treated with 131I therapy for the first time were included. Ninety-six patients (group 1) were given prednisolone (25 mg daily for 30 days beginning 2 days before 131I therapy) because of present or previous mild ophthalmopathy or the presence of risk factors (tobacco smoking and high concentrations of TSH-receptor antibodies) for developing this complication. One hundred and eleven patients received 131I therapy without prednisolone prophylaxis (group 2). Results: The patients in group 1 were younger than those in group 2 (44.6±12.0 years versus 51.3±15.1 years; P = 0.001). At 1 year post therapy the patients were classified as hypothyroid, euthyroid or hyperthyroid. In group 1, the numbers of patients were 23, 35 and 38, respectively, while the corresponding numbers in group 2 were 26, 40 and 45, respectively (P = 0.99 between groups). The cure rate (attainment of euthyroidism or hypothyroidism) was 60% in group 1 and 59% in group 2 (P = 0.97). No significant between-group difference was found, neither in the median time-interval until development of hypothyroidism nor until recurrence of the hyperthyroid-ism. Using logistic regression the cure rate correlated negatively with age (P = 0.041) and the size of the thyroid gland (P = 0.010) and positively with serum TSH at treatment (P = 0.034), whereas no significant impact was found for the use of prednisolone, gender, smoking, presence of anti-thyroid peroxidase antibodies, use of anti-thyroid drugs or the presence of eye symptoms. Conclusions: Although glucocorticoids in some contexts seem to attenuate the radiation-induced oxidative stress this had no impact on the final outcome following 131I therapy of patients with Graves’ disease.

scholarly journals Morphological Characteristics of Different Rates of Dying

2018 ◽  
Vol 14 (4) ◽  
pp. 35-43 ◽  
Author(s):  
V. A. Putincev ◽  
D. V. Bogomolov ◽  
D. V. Sundukov
Keyword(s):  
Statistical Analysis ◽  
Classical Method ◽  
Scientific Evidence ◽  
Morphological Characteristics ◽  
Time Interval ◽  
Forensic Practice ◽  
Morphological Criteria ◽  
Study Results ◽  
First Time ◽  
Further Development

The purpose of the study: scientific evidence and development of accessible morphological criteria that allow to determine the duration of dying and the rate of dying.Materials and methods. The material of the main study included 206 identified deaths of persons with different pre-known processes of dying, which served as criterion for selection from1500 deaths (n=206, 14%). Of these, 110 cases were observed by the forensic medical expertize, 79 cases were revealed by the forensic medical examination of the dead body and 17 cases were included after the postmortem autopsy. The sample included from 30 to 57 cases subdivided in 5 groups. 53 cases were selected for the first time interval, 30 observations for the second one, 32 observations for the third one, 34 observations for the fourth one and 57 observations for the fifth time interval. The following methods were used to study the material: analysis of information about the circumstances of death (based on the records), retrospective clinical and anatomical analysis, the main (classical) method of autopsy of human corpses in sectional studies and histological examination. In addition, an immunohistochemical test, as well as morphometric, macroscopic and photographic methods were used. For the accuracy and reliability of the findings, morphological and statistical analysis was used, which included both statistical analysis of morphological characteristics and tanatogenetic analysis of the cases of the sampled material.Study results. We developed and scientifically proved a methodology for determining 5 rates of dying according to the morphological characteristics systematized in morphological complexes: fulminant rate ≤15-30 min; fast rate >30 min — ≤2 h; moderate rate >2 — ≤6 h; slow rate >6 — ≤12 h; lingering rate >12 h. Approbation of the proposed method on the gross experimental material allowed to set the diagnostic limit of the total significance for each morphological complex, and thereby, to improve the methodology of establishing the rate of dying in accordance to the morphological characteristics for the use in forensic practice.Conclusion. The morphological complexes of the rate of dying established in this work would serve as a base for further development of not only forensic thanatology, but also for the aim of improving the medical and preventive care.

scholarly journals X-raying winds in distant quasars: The first high-redshift wind duty cycle

2020 ◽  
Vol 638 ◽  
pp. A136
Author(s):  
E. Bertola ◽  
M. Dadina ◽  
M. Cappi ◽  
C. Vignali ◽  
G. Chartas ◽  
...  
Keyword(s):  
Duty Cycle ◽  
High Redshift ◽  
Cosmic Time ◽  
Theoretical Models ◽  
Host Galaxy ◽  
Time Interval ◽  
Absorption Column ◽  
X Ray ◽  
Spatially Resolved ◽  
First Time

Aims. Theoretical models of wind-driven feedback from active galactic nuclei (AGN) often identify ultra-fast outflows as being the main agent in the generation of galaxy-sized outflows, which are possibly the main actors in establishing so-called AGN-galaxy co-evolution. Ultra-fast outflows are well characterized in local AGN but much less is known in quasars at the cosmic time when star formation and AGN activity peaked (z ≃ 1–3). It is therefore necessary to search for evidence of ultra-fast outflows in high-z sources to test wind-driven AGN feedback models. Methods. Here we present a study of Q2237+030, the Einstein Cross, a quadruply-imaged radio-quiet lensed quasar located at z = 1.695. We performed a systematic and comprehensive temporally and spatially resolved X-ray spectral analysis of all the available Chandra and XMM-Newton data (as of September 2019). Results. We find clear evidence for spectral variability, possibly due to absorption column density (or covering fraction) variability intrinsic to the source. For the first time in this quasar, we detect a fast X-ray wind outflowing at vout ≃ 0.1c that would be powerful enough (Ėkin ≃ 0.1 Lbol) to significantly affect the evolution of the host galaxy. We report also on the possible presence of an even faster component of the wind (vout ∼ 0.5c). For the first time in a high-z quasar, given the large sample and long time interval spanned by the analyzed X-ray data, we are able to roughly estimate the wind duty cycle as ≃0.46 (0.31) at 90% (95%) confidence level. Finally, we also confirm the presence of a Fe Kα emission line with variable energy, which we discuss in the light of microlensing effects as well as considering our findings on the source.

scholarly journals The Early History of Moscow: 14C Dates from Red Square

Radiocarbon ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 583-589 ◽  
Author(s):  
Alexander L. Alexandrovskiy ◽  
Johannes Van Der Plicht ◽  
Nikolay Krenke ◽  
Olga Chichagova ◽  
Nikolai Kovaliukh ◽  
...  
Keyword(s):  
Early History ◽  
Time Interval ◽  
Cultural Layer ◽  
Rural Settlements ◽  
13Th Century ◽  
History Of ◽  
Historical Center ◽  
First Time ◽  
Archaeological Excavations

For the first time, a series of 14C dates has been obtained for samples from the archaeological excavations in Red Square, the historical center of Moscow. The remains of burned dwellings from the bottom of the cultural layer were dated as well as dispersed charcoal from the underlying plough soil. The results correspond to a 200-yr time interval and prove that arable activity at the site began as early as the late 11th century ad. The field belonged to Moscow itself or to rural settlements nearby. The oldest dwelling was built ca. the late 12th–early 13th century ad.

scholarly journals Designing and validating a PVA liver phantom with respiratory motion for needle-based interventions

2019 ◽  
Vol 14 (12) ◽  
pp. 2177-2186 ◽  
Author(s):  
Tonke L. de Jong ◽  
Adriaan Moelker ◽  
Jenny Dankelman ◽  
John J. van den Dobbelsteen
Keyword(s):  
Respiratory Motion ◽  
Liver Phantom

LMC X–4: Different Types of Long-Term Variability

2017 ◽  
Vol 14 (S339) ◽  
pp. 146-146
Author(s):  
S. Molkov
Keyword(s):  
Binary Systems ◽  
Noise Model ◽  
High Mass ◽  
Time Interval ◽  
Spin Torque ◽  
X Ray ◽  
Spin Period ◽  
Different Types ◽  
First Time

AbstractThis talk presented a summary of our study of different types of long-term variability in the high-mass X-ray binary LMC X-4, by taking advantage of more than 43 years of measurements in the X-ray domain. In particular, we investigated the 30-day cycle of modulation of the X-ray emission from the source (super-orbital or precessional variability), and refined the orbital period and its first derivative. We showed that the precession period in the time-interval 1991–2015 is near its equilibrium value of Psup = 30.370 days, while the observed historical changes in the phase of this variability can be interpreted in terms of the ‘red noise’ model. We obtained an analytical law from which the precession phase can be determined to within 5% throughout the entire time-interval under consideration. Our analysis revealed for the first time that the source is displaying near-periodic variations of its spin period, on a time-scale of roughly 6.8 years, thus making LMC X-4 one of the (few) known binary systems that show remarkable long-term spin–torque reversals.

scholarly journals Cribrilinid bryozoans from Pleistocene Mediterranean deep-waters, with the description of new species

2020 ◽  
pp. 1-23
Author(s):  
Antonietta Rosso ◽  
Emanuela Di Martino ◽  
Andrew N. Ostrovsky
Keyword(s):  
New Species ◽  
Deep Water ◽  
Time Interval ◽  
New Combinations ◽  
Mediterranean Species ◽  
Growth Morphology ◽  
Deep Waters ◽  
First Time

Abstract Cribrilinid bryozoans originating from Pleistocene deep-water sediments from two localities near Messina (Sicily, Italy)—Capo Milazzo (Gelasian) and Scoppo (Calabrian)—were examined. Five cribrilinid species were found, three in each locality and time interval, with only one species shared. Three species, Cribrilaria profunda n. sp., Glabrilaria transversocarinata n. sp., and Figularia spectabilis n. sp., are new to science. Of the two remaining species, Figularia figularis was already known from local fossil associations, whereas Glabrilaria pedunculata, a present-day Mediterranean species, is recorded for the first time as a fossil. New combinations are suggested for two species previously assigned to Puellina, Cribrilaria saldanhai (Harmelin, 2001) n. comb. and Cribrilaria mikelae (Harmelin, 2006) n. comb. The diagnosis of the genus Figularia was amended to include an erect growth morphology in addition to the encrusting form, and the occurrence of ooecia formed by the distal kenozooid. Following a literature revision of all species currently assigned to Figularia, the new combinations Vitrimurella capitifera (Canu and Bassler, 1929) n. comb. and Hayamiellina quaylei (Powell, 1967a) n. comb. are suggested, and problematic species are listed and briefly discussed. UUID: http://zoobank.org/b7b36152-bf7b-4e00-b6ec-2614b2a58f1b

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