848 research outputs found
Two paths of cluster evolution: global expansion versus core collapse
All gravitationally bound clusters expand, due to both gas loss from their
most massive members and binary heating. All are eventually disrupted tidally,
either by passing molecular clouds or the gravitational potential of their host
galaxies. However, their interior evolution can follow two very different
paths. Only clusters of sufficiently large initial population and size undergo
the combined interior contraction and exterior expansion that leads eventually
to core collapse. In all other systems, core collapse is frustrated by binary
heating. These clusters globally expand for their entire lives, up to the point
of tidal disruption.
Using a suite of direct N-body calculations, we trace the "collapse line" in
r_v-N space that separates these two paths. Here, r_v and N are the cluster's
initial virial radius and population, respectively. For realistic starting
radii, the dividing N-value is from 10^4 to over 10^5. We also show that there
exists a minimum population, N_min, for core collapse. Clusters with N < N_min
tidally disrupt before core collapse occurs. At the Sun's Galactocentric
radius, R_G = 8.5 kpc, we find N_min >~ 300. The minimum population scales with
Galactocentric radius as R_G^{-9/8}.
The position of an observed cluster relative to the collapse line can be used
to predict its future evolution. Using a small sample of open clusters, we find
that most lie below the collapse line, and thus will never undergo core
collapse. Most globular clusters, on the other hand, lie well above the line.
In such a case, the cluster may or may not go through core collapse, depending
on its initial size. We show how an accurate age determination can help settle
this issue.Comment: Accepted for publication in MNRAS. 14 Pages, 9 Figures, 2 Table
Prevalence, incidence, and risk factors for shoulder and neck dysfunction after neck dissection: a systematic review
Introduction
Shoulder pain and dysfunction may occur following neck dissection among people being treated for head and neck cancer. This systematic review aims to examine the prevalence and incidence of shoulder and neck dysfunction after neck dissection and identify risk factors for these post-operative complications.
Methods
Electronic databases (Pubmed, CINAHL, EMBASE, Cochrane) were searched for articles including adults undergoing neck dissection for head and neck cancer. Studies that reported prevalence, incidence or risk factors for an outcome of the shoulder or neck were eligible and assessed using the Critical Review Form – Quantitative Studies.
Results
Seventy-five articles were included in the final review. Prevalence rates for shoulder pain were slightly higher after RND (range, 10–100%) compared with MRND (range, 0–100%) and SND (range, 9–25%). The incidence of reduced shoulder active range of motion depended on surgery type (range, 5–20%). The prevalence of reduced neck active range of motion after neck dissection was 1–13%. Type of neck dissection was a risk factor for shoulder pain, reduced function and health-related quality of life.
Conclusions
The prevalence and incidence of shoulder and neck dysfunction after neck dissection varies by type of surgery performed and measure of dysfunction used. Pre-operative education for patients undergoing neck dissection should acknowledge the potential for post-operative shoulder and neck problems to occur and inform patients that accessory nerve preservation lowers, but does not eliminate, the risk of developing musculoskeletal complications
Relationships of Cetacea (Artiodactyla) Among Mammals: Increased Taxon Sampling Alters Interpretations of Key Fossils and Character Evolution
BACKGROUND: Integration of diverse data (molecules, fossils) provides the most robust test of the phylogeny of cetaceans. Positioning key fossils is critical for reconstructing the character change from life on land to life in the water. METHODOLOGY/PRINCIPAL FINDINGS: We reexamine relationships of critical extinct taxa that impact our understanding of the origin of Cetacea. We do this in the context of the largest total evidence analysis of morphological and molecular information for Artiodactyla (661 phenotypic characters and 46,587 molecular characters, coded for 33 extant and 48 extinct taxa). We score morphological data for Carnivoramorpha, Creodonta, Lipotyphla, and the raoellid artiodactylan Indohyus and concentrate on determining which fossils are positioned along stem lineages to major artiodactylan crown clades. Shortest trees place Cetacea within Artiodactyla and close to Indohyus, with Mesonychia outside of Artiodactyla. The relationships of Mesonychia and Indohyus are highly unstable, however--in trees only two steps longer than minimum length, Mesonychia falls inside Artiodactyla and displaces Indohyus from a position close to Cetacea. Trees based only on data that fossilize continue to show the classic arrangement of relationships within Artiodactyla with Cetacea grouping outside the clade, a signal incongruent with the molecular data that dominate the total evidence result. CONCLUSIONS/SIGNIFICANCE: Integration of new fossil material of Indohyus impacts placement of another extinct clade Mesonychia, pushing it much farther down the tree. The phylogenetic position of Indohyus suggests that the cetacean stem lineage included herbivorous and carnivorous aquatic species. We also conclude that extinct members of Cetancodonta (whales+hippopotamids) shared a derived ability to hear underwater sounds, even though several cetancodontans lack a pachyostotic auditory bulla. We revise the taxonomy of living and extinct artiodactylans and propose explicit node and stem-based definitions for the ingroup
Human uterine and placental arteries exhibit tissue-specific acute responses to 17β-estradiol and estrogen-receptor-specific agonists
The discrete regulation of vascular tone in the human uterine and placental circulations is a key determinant of appropriate uteroplacental blood perfusion and pregnancy success. Humoral factors such as estrogen, which increases in the placenta and maternal circulation throughout human pregnancy, may regulate these vascular beds as studies of animal arteries have shown that 17β-estradiol, or agonists of estrogen receptors (ER), can exert acute vasodilatory actions. The aim of this study was to compare how acute exposure to ER-specific agonists, and 17β-estradiol, altered human placental and uterine arterial tone in vitro. Uterine and placental arteries were isolated from biopsies obtained from women with uncomplicated pregnancy delivering a singleton infant at term. Vessels were mounted on a wire myograph, exposed to the thromboxane receptor agonist U46619 (10(−6) M), and then incubated with incremental doses (5 min, 0.03–30 µM) of either 17β-estradiol or agonists specific for the ERs ERα (PPT), ERβ (DPN) or the G-protein-coupled estrogen receptor GPER-1 (G1). ERα and ERβ mRNA expression was assessed. 17β-estradiol, PPT and DPN each relaxed myometrial arteries (P < 0.05) in a manner that was partly endothelium-dependent. In contrast, 17β-estradiol or DPN relaxed placental arteries (maximum relaxation to 42 ± 1.1 or 47.6 ± 6.53% of preconstriction, respectively) to a lesser extent than myometrial arteries (to 0.03 ± 0.03 or 8.0 ± 1.0%) and in an endothelial-independent manner whereas PPT was without effect. G1 exposure did not inhibit the constriction of myometrial nor placenta arteries. mRNA expression of ERα and ERβ was greater in myometrial arteries than placental arteries. ER-specific agonists, and 17β-estradiol, differentially modulate the tone of uterine versus placental arteries highlighting that estrogen may regulate human uteroplacental blood flow in a tissue-specific manner
The impact of physical, psychological, and sexual intimate partner violence on women's mental health: depressive symptoms, posttraumatic stress disorder, state anxiety, and suicide
Objective: This study aimed to determine the impact of lifetime physical, psychological, and
sexual intimate male partner violence (IPV) on the mental health of women, after controlling
for the contribution of lifetime victimization. The comorbidity of depressive symptoms and
posttraumatic stress disorder (PTSD) and their relation to state anxiety and suicide were also
assessed.
Methods: Physically/psychologically (n 75) and psychologically abused women (n 55)
were compared with nonabused control women (n 52). Information about sociodemographic
characteristics, lifetime victimization, and mental health status (depressive and state anxiety
symptoms, PTSD, and suicide) was obtained through face-to-face structured interviews.
Results: Women exposed to physical/psychological and psychological IPV had a higher incidence
and severity of depressive and anxiety symptoms, PTSD, and thoughts of suicide than
control women, with no differences between the two abused groups. The concomitance of
sexual violence was associated with a higher severity of depressive symptoms in both abused
groups and a higher incidence of suicide attempts in the physically/psychologically abused
group. The incidence of PTSD alone was very rare, and depressive symptoms were either
alone or comorbid with PTSD. The severity of state anxiety was higher in abused women
with depressive symptoms or comorbidity, as was the incidence of suicidal thoughts in the
physically/psychologically abused group. Lifetime victimization was not a predictor of the
deterioration of mental health in this study.
Conclusions: These findings indicate that psychological IPV is as detrimental as physical
IPV, with the exception of effects on suicidality, which emphasizes that psychological IPV
should be considered a major type of violence by all professionals involved.Este es un artículo ampliamente citado internacionalmente respeto a violencia de pareja y consecuencias en la salud de las mujeres
Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1
Peer reviewedPublisher PD
Hypoglycemia Assessed by Continuous Glucose Monitoring Is Associated with Preclinical Atherosclerosis in Individuals with Impaired Glucose Tolerance
Hypoglycemia is associated with increased risk of cardiovascular adverse clinical outcomes. There is evidence that impaired glucose tolerance (IGT) is associated with cardiovascular morbidity and mortality. Whether IGT individuals have asymptomatic hypoglycemia under real-life conditions that are related to early atherosclerosis is unknown. To this aim, we measured episodes of hypoglycemia during continuous interstitial glucose monitoring (CGM) and evaluated their relationship with early manifestation of vascular atherosclerosis in glucose tolerant and intolerant individuals. An oral glucose tolerance test (OGTT) was performed in 79 non-diabetic subjects. Each individual underwent continuous glucose monitoring for 72 h. Cardiovascular risk factors and ultrasound measurement of carotid intima-media thickness (IMT) were evaluated. IGT individuals had a worse cardiovascular risk profile, including higher IMT, and spent significantly more time in hypoglycemia than glucose-tolerant individuals. IMT was significantly correlated with systolic (r = 0.22; P = 0.05) and diastolic blood pressure (r = 0.28; P = 0.01), total (r = 0.26; P = 0.02) and LDL cholesterol (r = 0.27; P = 0.01), 2-h glucose (r = 0.39; P<0.0001), insulin sensitivity (r = −0.26; P = 0.03), and minutes spent in hypoglycemia (r = 0.45; P<0.0001). In univariate analyses adjusted for gender, minutes spent in hypoglycemia were significantly correlated with age (r = 0.26; P = 0.01), waist circumference (r = 0.33; P = 0.003), 2-h glucose (r = 0.58; P<0.0001), and 2-h insulin (r = 0.27; P = 0.02). In a stepwise multivariate regression analysis, the variables significantly associated with IMT were minutes spent in hypoglycemia (r2 = 0.252; P<0.0001), and ISI index (r2 = 0.089; P = 0.004), accounting for 34.1% of the variation. Episodes of hypoglycemia may be considered as a new potential cardiovascular risk factor for IGT individuals
Genital HSV-2 Infection Induces Short-Term NK Cell Memory
NK cells are known as innate immune cells that lack immunological memory. Recently, it has been shown that NK cells remember encounters with chemical haptens that induce contact hypersensitivity and cytomegalovirus infection. Here, we show the existence of NK cell memory following HSV-2 infection. Stimulation with HSV-2 Ags led to higher IFNγ production in NK cells that were exposed 30 days previously to HSV-2, compared to NK cells from naïve mice. More importantly, this increased production of IFNγ in NK cells was independent of B- and T- lymphocytes and specific for the HSV-2 Ags. We also showed that previously exposed NK cells in a B- and T-lymphocyte free environment mediate protection against HSV-2 infection and they are necessary for the protection of mice against HSV-2 infection. Collectively, NK cells remember prior HSV-2 encounters independent of B- and T- lymphocytes leading to protection against HSV-2 mediated morbidity and mortality upon re-exposure
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Early changes in apoplast composition associated with defence and disease in interactions between Phaseolus vulgaris and the halo blight pathogen Pseudomonas syringae pv. phaseolicola
The apoplast is the arena in which endophytic pathogens such as Pseudomonas syringae grow and interact with plant cells. Using metabolomic and ion analysis techniques, this study shows how the composition of Phaseolus vulgaris leaf apoplastic fluid changes during the first six hours of compatible and incompatible interactions with two strains of Pseudomonas syringae pv. phaseolicola (Pph) that differ in the presence of the genomic island PPHGI-1. Leaf inoculation with the avirulent island-carrying strain Pph 1302A elicited effector-triggered immunity (ETI) and resulted in specific changes in apoplast composition, including increases in conductivity, pH, citrate, γ-aminobutyrate (GABA) and K+, that are linked to the onset of plant defence responses. Other apoplastic changes, including increases in Ca2+, Fe2/3+ Mg2+, sucrose, β-cyanoalanine and several amino acids, occurred to a relatively similar extent in interactions with both Pph 1302A and the virulent, island-less strain Pph RJ3. Metabolic footprinting experiments established that Pph preferentially metabolizes malate, glucose and glutamate, but excludes certain other abundant apoplastic metabolites, including citrate and GABA, until preferred metabolites are depleted. These results demonstrate that Pph is well-adapted to the leaf apoplast metabolic environment and that loss of PPHGI-1 enables Pph to avoid changes in apoplast composition linked to plant defences
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