270 research outputs found
Modeling nuclear dynamics in the age of multimessenger astrophysics
Understanding the properties of dense and cold nuclear matter, which is expected to characterize the neutron star core, is one of the challenges of modern physics. In this Thesis we have explored the effect of including relativistic boost corrections within the derivation of a realistic nuclear effective potential—carried out from a phenomenological Hamiltonian using the formalism of correlated basis function and cluster expansion techniques—describing the interactions between nucleons in the nuclear medium. Our work highlighted the importance of developing a consistent treatment of boost corrections and three-nucleon forces. Indeed it should be kept in mind that the introduction of such relativistic corrections must be complemented with a softening of the isoscalar three-nucleon repulsion, which strongly affects the high density behavior of nuclear matter. For this reason we also present the results of a pioneering study aimed at inferring information on the three-nucleon repulsion from multimessenger neutron star observations. We have performed bayesian inference employing the currently available multimessenger datasets in order to constrain the coupling constant of three-nucleon repulsion in dense matter
Unexpected Metastasis of High Grade Serous Ovarian Cancer to Breast: Case Report and Literature Review
Introduction: Metastasis of ovarian serous carcinoma to breast and/or axillary lymph nodes represents an unusual event. Nevertheless, their detection and distinction from mammary carcinoma are of huge clinical importance because the treatment and prognosis diverge significantly. Case presentation: We report a case of a 47 year-old Caucasian female patient with unforeseen metastasis to the breast and to axillary lymph nodes due to ovarian serous carcinoma. Conclusion: In patients with history of OSC who present with axillary or breast mass, an accurate histological diagnosis should be obtained since this has a great impact on treatment outcomes
Sensitivity of Neutron Star Observations to Three-nucleon Forces
Astrophysical observations of neutron stars have been widely used to infer
the properties of the nuclear matter equation of state. Beside being a source
of information on average properties of dense matter, however, the data
provided by electromagnetic and gravitational wave (GW) facilities are reaching
the accuracy needed to constrain, for the first time, nuclear dynamics in dense
matter. In this work we assess the sensitivity of current and future neutron
star observations to directly infer the strength of repulsive three-nucleon
forces, which are key to determine the stiffness of the equation of state.
Using a Bayesian approach we focus on the constraints that can be derived on
three-body interactions from binary neutron star mergers observed by second and
third-generation of gravitational wave interferometers. We consider both single
and multiple observations. For current detectors at design sensitivity the
analysis suggests that only low mass systems, with large signal-to-noise ratios
(SNR), allow to reliably constrain the three-body forces. However, our results
show that a single observation with a third-generation interferometer, such as
the Einstein Telescope or Cosmic Explorer, will constrain the strength of the
repulsive three-body potential with exquisite accuracy, turning
third-generation GW detectors into new laboratories to study the nucleon
dynamics.Comment: Minor changes to improve the discussion of the results. Technical
details added to extend the equation of state descriptio
Conformational Changes of Calpain from Human Erythrocytes in the Presence of Ca2
Small angle x-ray scattering has been used to monitor calpain structural transitions during the activation process triggered by Ca(2+) binding. The scattering pattern of the unliganded enzyme in solution does not display any significant difference with that calculated from the crystal structure. The addition of Ca(2+) promotes the formation of large aggregates, indicating the exposure of hydrophobic patches on the surface of the protease. In contrast, Ca(2+) addition in the presence of the thiol proteinase inhibitor E64 or of the inhibitor leupeptin causes a small conformational change with no dissociation of the heterodimer. The resulting conformation appears to be slightly more extended than the unliganded form. From the comparison between ab initio models derived from our data with the crystal structure, the major observable conformational change appears to be localized at level of the L-subunit and in particular seems to confirm the mutual movement already observed by the crystallographic analysis of the dII (dIIb) and the dI (dIIa) domains creating a functional active site. This work not only provides another piece of supporting evidence for the calpain conformational change in the presence of Ca(2+), but actually constitutes the first experimental observation of this change for intact heterodimeric calpain in solution
Controlled spermatozoa–oocyte interaction improves embryo quality in sheep
The current protocols of in vitro fertilization and culture in sheep rely on paradigms established more than 25 years ago, where Metaphase II oocytes are co-incubated with capacitated spermatozoa overnight. While this approach maximizes the number of fertilized oocytes, on the other side it exposes them to high concentration of reactive oxygen species (ROS) generated by active and degenerating spermatozoa, and positively correlates with polyspermy. Here we set up to precisely define the time frame during which spermatozoa effectively penetrates and fertilizes the oocyte, in order to drastically reduce spermatozoa-oocyte interaction. To do that, in vitro matured sheep oocytes co-incubated with spermatozoa in IVF medium were sampled every 30 min (start of incubation time 0) to verify the presence of a fertilizing spermatozoon. Having defined the fertilization time frame (4 h, data from 105 oocytes), we next compared the standard IVF procedures overnight (about 16 h spermatozoa/oocyte exposure, group o/nIVF) with a short one (4 h, group shIVF). A lower polyspermic fertilization (> 2PN) was detected in shIVF (6.5%) compared to o/nIVF (17.8%), P < 0.05. The o/nIVF group resulted in a significantly lower 2-cell stage embryos, than shIVF [34.6% (81/234) vs 50.6% (122/241) respectively, P < 0.001]. Likewise, the development to blastocyst stage confirmed a better quality [29% (70/241) vs 23.5% (55/234), shIVF vs o/nIVF respectively] and an increased Total Cell Number (TCN) in shIVF embryos, compared with o/n ones. The data on ROS have confirmed that its generation is IVF time-dependent, with high levels in the o/nIVF group. Overall, the data suggest that a shorter oocyte-spermatozoa incubation results in an improved embryo production and a better embryo quality, very likely as a consequence of a shorter exposure to the free oxygen radicals and the ensuing oxidative stress imposed by overnight culture
SMC framework in motion control systems
Design of a motion control system should take into account both the unconstrained motion performed without interaction with environment or other system, and the constrained motion where system is in contact with environment or has certain functional interaction with another system. In this paper control systems design approach, based on siding mode methods, that allows selection of control for generic tasks as trajectory and/or force tracking as well as for systems that require maintain some functional relation like bilateral or multilateral systems, establisment of virtual relation among mobile robots or control of haptic systems is presented. It is shown that all basic motion control problems - trajectory tracking, force control, hybrid position/force control scheme and the impedance control - can be treated in the same way while avoiding the structural change of the controller and guarantying stable behavior of the system In order to show applicability of the proposed techniques simulation and experimental results for high precision systems in microsystems assembly tasks and bilateral control systems are presente
Controlled spermatozoa-oocyte interaction improves embryo quality in sheep
The current protocols of in vitro fertilization and culture in sheep rely on paradigms established more than 25 years ago, where Metaphase II oocytes are co-incubated with capacitated spermatozoa overnight. While this approach maximizes the number of fertilized oocytes, on the other side it exposes them to high concentration of reactive oxygen species (ROS) generated by active and degenerating spermatozoa, and positively correlates with polyspermy. Here we set up to precisely define the time frame during which spermatozoa effectively penetrates and fertilizes the oocyte, in order to drastically reduce spermatozoa-oocyte interaction. To do that, in vitro matured sheep oocytes co-incubated with spermatozoa in IVF medium were sampled every 30 min (start of incubation time 0) to verify the presence of a fertilizing spermatozoon. Having defined the fertilization time frame (4 h, data from 105 oocytes), we next compared the standard IVF procedures overnight (about 16 h spermatozoa/oocyte exposure, group o/nIVF) with a short one (4 h, group shIVF). A lower polyspermic fertilization (> 2PN) was detected in shIVF (6.5%) compared to o/nIVF (17.8%), P < 0.05. The o/nIVF group resulted in a significantly lower 2-cell stage embryos, than shIVF [34.6% (81/234) vs 50.6% (122/241) respectively, P < 0.001]. Likewise, the development to blastocyst stage confirmed a better quality [29% (70/241) vs 23.5% (55/234), shIVF vs o/nIVF respectively] and an increased Total Cell Number (TCN) in shIVF embryos, compared with o/n ones. The data on ROS have confirmed that its generation is IVF time-dependent, with high levels in the o/nIVF group. Overall, the data suggest that a shorter oocyte-spermatozoa incubation results in an improved embryo production and a better embryo quality, very likely as a consequence of a shorter exposure to the free oxygen radicals and the ensuing oxidative stress imposed by overnight culture
Update on gingival overgrowth by cyclosporine A in renal transplants
Severe gingival overgrowth is one of the most frequent side effects in renal transplant patients associated with assumption of cyclosporine A. Several associations with age, sex, dosage, duration of therapy or interval since transplantation have been hypothesized. The introduction of alternative immunosuppressant drugs have been suggested to permit better long-term transplant outcomes and a decrease in incidence of gingival overgrowth. The aim of the present paper is to summarize current knowledge regarding aetiology, pathogenesis and management of gingival overgrowth induced by Cyclosporine A
A score system for complete cytoreduction in selected recurrent ovarian cancer patients undergoing secondary cytoreductive surgery: predictors- and nomogram-based analyses
Objective: To test the applicability of the Arbeitsgemeinschaft Gyn\ue4kologische Onkologie (AGO) and Memorial Sloan Kettering (MSK) criteria in predicting complete cytoreduction (CC) in patients undergoing secondary cytoreductive surgery (SCS) for recurrent ovarian cancer (ROC). Methods: Data of consecutive patients undergoing SCS were reviewed. The Arbeitsgemeinschaft Gyn\ue4kologische Onkologie OVARian cancer study group (AGO-OVAR) and MSK criteria were retrospectively applied. Nomograms, based on AGO criteria, MSK criteria and both AGO and MSK criteria were built in order to assess the probability to achieve CC at SCS. Results: Overall, 194 patients met the inclusion criteria. CC was achieved in 161 (82.9%) patients. According to the AGO-OVAR criteria, we observed that CC was achieved in 87.0% of patients with positive AGO score. However, 45 out of 71 (63.4%) patients who did not fulfilled the AGO score had CC. Similarly, CC was achieved in 87.1%, 61.9% and 66.7% of patients for whom SCS was recommended, had to be considered and was not recommended, respectively. In order to evaluate the predictive value of the AGO-OVAR and MSK criteria we built 2 separate nomograms (c-index: 0.5900 and 0.5989, respectively) to test the probability to achieve CC at SCS. Additionally, we built a nomogram using both the aforementioned criteria (c-index: 0.5857). Conclusion: The AGO and MSK criteria help identifying patients deserving SCS. However, these criteria might be strict, thus prohibiting a beneficial treatment in patients who do not met these criteria. Further studies are needed to clarify factors predicting CC at SC
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