6,989 research outputs found
Olaparib treatment for BRCA-mutant ovarian cancer with leptomeningeal disease
HIGHLIGHTS: Leptomeningeal disease occurs more commonly in BRCA-mutated ovarian cancer; A clinically significant dose of olaprib is able to penetrate the leptomeninges; Leptomeningeal metastases in a BRCA-mutated ovarian cancer responded to olaparib
Role of Androgens in Female Genitourinary Tissue Structure and Function: Implications in the Genitourinary Syndrome of Menopause.
Abstract Introduction Genitourinary conditions in women increase in prevalence with age. Androgens are prerequisite hormones of estrogen biosynthesis, are produced in larger amounts than estrogens in women, and decrease throughout adulthood. However, research and treatment for genitourinary complaints have traditionally focused on estrogens to the exclusion of other potential hormonal influences. Aim To summarize and evaluate the evidence that androgens are important for maintaining genitourinary health in women and that lack of androgenic activity can contribute to the development of symptoms of the genitourinary syndrome of menopause. Methods The role of androgens in the pathophysiology, diagnosis, and treatment of genitourinary syndrome of menopause was discussed by an international and multidisciplinary panel during a consensus conference organized by the International Society for the Study of Women's Sexual Health. A subgroup further examined publications from the PubMed database, giving preference to clinical studies or to basic science studies in human tissues. Main Outcome Measures Expert opinion evaluating trophic and functional effects of androgens, their differences from estrogenic effects, and regulation of androgen and estrogen receptor expression in female genitourinary tissues. Results Androgen receptors have been detected throughout the genitourinary system using immunohistochemical, western blot, ligand binding, and gene expression analyses. Lower circulating testosterone and estradiol concentrations and various genitourinary conditions have been associated with differential expression of androgen and estrogen receptors. Supplementation of androgen and/or estrogen in postmenopausal women (local administration) or in ovariectomized animals (systemic administration) induces tissue-specific responses that include changes in androgen and estrogen receptor expression, cell growth, mucin production, collagen turnover, increased perfusion, and neurotransmitter synthesis. Conclusion Androgens contribute to the maintenance of genitourinary tissue structure and function. The effects of androgens can be distinct from those of estrogens or can complement estrogenic action. Androgen-mediated processes might be involved in the full or partial resolution of genitourinary syndrome of menopause symptoms in women. Traish AM, Vignozzi L, Simon JA, et al. Role of Androgens in Female Genitourinary Tissue Structure and Function: Implications in the Genitourinary Syndrome of Menopause. Sex Med Rev 2018;6:558–571
Group-theoretical approach to a non-central extension of the Kepler-Coulomb problem
Bound and scattering states of a non-central extension of the
three-dimensional Kepler-Coulomb Hamiltonian are worked out analytically within
the framework of the potential groups of the problem, SO(7) for bound states
and SO(6,1) for scattering states. In the latter case, the S matrix is
calculated by the method of intertwining operators.Comment: 12 pages, to appear in J. Phys. A : Math. Theo
Maladaptation and the paradox of robustness in evolution
Background. Organisms use a variety of mechanisms to protect themselves
against perturbations. For example, repair mechanisms fix damage, feedback
loops keep homeostatic systems at their setpoints, and biochemical filters
distinguish signal from noise. Such buffering mechanisms are often discussed in
terms of robustness, which may be measured by reduced sensitivity of
performance to perturbations. Methodology/Principal Findings. I use a
mathematical model to analyze the evolutionary dynamics of robustness in order
to understand aspects of organismal design by natural selection. I focus on two
characters: one character performs an adaptive task; the other character
buffers the performance of the first character against perturbations. Increased
perturbations favor enhanced buffering and robustness, which in turn decreases
sensitivity and reduces the intensity of natural selection on the adaptive
character. Reduced selective pressure on the adaptive character often leads to
a less costly, lower performance trait. Conclusions/Significance. The paradox
of robustness arises from evolutionary dynamics: enhanced robustness causes an
evolutionary reduction in the adaptive performance of the target character,
leading to a degree of maladaptation compared to what could be achieved by
natural selection in the absence of robustness mechanisms. Over evolutionary
time, buffering traits may become layered on top of each other, while the
underlying adaptive traits become replaced by cheaper, lower performance
components. The paradox of robustness has widespread implications for
understanding organismal design
The environmental impact of climate change adaptation on land use and water quality
Encouraging adaptation is an essential aspect of the policy response to climate change1. Adaptation seeks to reduce the harmful consequences and harness any beneficial opportunities arising from the changing climate. However, given that human activities are the main cause of environmental transformations worldwide2, it follows that adaptation itself also has the potential to generate further pressures, creating new threats for both local and global ecosystems. From this perspective, policies designed to encourage adaptation may conflict with regulation aimed at preserving or enhancing environmental quality. This aspect of adaptation has received relatively little consideration in either policy design or academic debate. To highlight this issue, we analyse the trade-offs between two fundamental ecosystem services that will be impacted by climate change: provisioning services derived from agriculture and regulating services in the form of freshwater quality. Results indicate that climate adaptation in the farming sector will generate fundamental changes in river water quality. In some areas, policies that encourage adaptation are expected to be in conflict with existing regulations aimed at improving freshwater ecosystems. These findings illustrate the importance of anticipating the wider impacts of human adaptation to climate change when designing environmental policies
Vacuum Ambiguity in de Sitter Space at Strong Coupling
It is well known that in the weak coupling regime, quantum field theories in
de Sitter space do not have a unique vacuum, but a class of vacua parametrized
by a complex parameter , i.e., the so-called -vacua. In this
article, using gauge/gravity duality, we calculate the symmetric two-point
function of strongly coupled supersymmetric Yang-Mills theory on
. We find that there is a class of de Sitter invariant vacua,
parametrized by a set of complex parameters .Comment: 17 pages in JHEP style, references adde
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