Fluid dynamics instabilities are usually investigated in two types of situations, either confined in cells with fixed boundaries, or free to grow in open space. In this article we study the Faraday ...instability triggered in a floating liquid lens. This is an intermediate situation in which a hydrodynamical instability develops in a domain with flexible boundaries. The instability is observed to be initially disordered with fluctuations of both the wave field and the lens boundaries. However, a slow dynamics takes place, leading to a mutual adaptation so that a steady regime is reached with a stable wave field in a stable lens contour. The most recurrent equilibrium lens shape is elongated with the Faraday wave vector along the main axis. In this self-organized situation an equilibrium is reached between the radiation pressure exerted by Faraday waves on the borders and their capillary response. The elongated shape is obtained theoretically as the exact solution of a Riccati equation with a unique control parameter and compared with the experiment.
Long-term potentiation (LTP) is a persistent increase in synaptic strength required for many behavioral adaptations, including learning and memory, visual and somatosensory system functional ...development, and drug addiction. Recent work has suggested a role for LTP-like phenomena in the processing of nociceptive information in the dorsal horn and in the generation of central sensitization during chronic pain states. Whereas LTP of glutamatergic and GABAergic synapses has been characterized throughout the central nervous system, to our knowledge there have been no reports of LTP at mammalian glycinergic synapses. Glycine receptors (GlyRs) are structurally related to GABA A receptors and have a similar inhibitory role. Here we report that in the superficial dorsal horn of the spinal cord, glycinergic synapses on inhibitory GABAergic neurons exhibit LTP, occurring rapidly after exposure to the inflammatory cytokine interleukin-1 beta. This form of LTP (GlyR LTP) results from an increase in the number and/or change in biophysical properties of postsynaptic glycine receptors. Notably, formalin-induced peripheral inflammation in vivo potentiates glycinergic synapses on dorsal horn neurons, suggesting that GlyR LTP is triggered during inflammatory peripheral injury. Our results define a previously unidentified mechanism that could disinhibit neurons transmitting nociceptive information and may represent a useful therapeutic target for the treatment of pain.
Cardiac catheterization through radial access is associated with significant ionizing radiation exposure for the operator. We aimed at evaluating whether a removable shield placed upon the patient ...could impact favorably on annual radiation exposure for the operator. We designed a pre–post study comparing radiation exposure in a total of five operators under standard protection procedures (first period) and after applying a removable shield (second period). Each period included all the procedures performed in 1 year. Radiation exposure was measured through three dosimeters on each operator. A total of 1610 procedures were performed during the first period, and 1670 during the second period. For each operator, Fluoroscopy Time (FT) per exam did not differ between the two periods (13.1 ± 1 vs 12.9 ± 2 min/exam,
p
= 0.73), whereas Dose-Area Product (DAP) per procedure was slightly higher in the second period (5.247 ± 651 vs 6.374 ± 967 mGy/cm
2
,
p
< 0.01). The use of a removable shield significantly reduced operators’ radiation dose at the left bracelet (64.3 ± 13.3 μSv/exam vs 23.8 ± 6.0 μSv/exam,
p
= 0.003). This remained significant even after adjustment for DAP per procedure (
p
= 0.015) and number of operators participating to each procedure (
p
= 0.013), whereas no significant difference was observed for card (5.6 ± 10.5 μSv/exam vs 0.9 ± 0.3 μSv/exam,
p
= 0.36) and neck bands (3.3 ± 4.5 μSv/exam vs 2.0 ± 2.0 μSv/exam,
p
= 0.36) dosimeters. The use of a removable shield during cardiac catheterization reduces radiation exposure at the level of the operator's upper limb, whereas no difference was found for other body parts. This may help in reducing radiation exposure of operator’s hand. DAP increase merits further investigation.
OBJECTIVE:Pulse pressure amplification (PPA) is considered a non-dimensional marker of early vascular ageing, and is inversely and independently associated to future CV events. It is acknowledged ...that PPA is influenced by heart rate (HR) and its related changes. We aimed at evaluating the effect of ageing on the HR dependence of PPA.
DESIGN AND METHOD:In a cohort of 675 never-treated hypertensives (age range 18 to 89 years, mean age 47 ± 11 years, 56% men), at low-to-intermediate CV risk and without signs of hypertension-mediated organ damage, PPA and simultaneous HR were calculated from radial tonometry and estimated aortic pressure waveform through a radial-to-aortic generalized transfer function (SphygmoCor). The significance of the interaction term “age (young=below mean, old=above mean) X HR” as an independent predictor of PPA, was tested in a linear multivariate regression model after accounting for the non-linearity of the relationship between age and PPA, and the effect of other confounders (sex, height, carotid-femoral pulse wave velocity).
RESULTS:Mean PPA was 1.28 ± 0.15, mean HR 66 ± 11 bpm. HR was positively and strongly correlated to PPA (p < 0.01), explaining one fifth of its variance. The curvilinear relationship between age and PPA was best described by an inverse logarithmic equation (p for R change vs linear = 0.04). The interaction term “age X HR” was positively related to PPA after adjusting for multiple confounders (p < 0.01). The slope of the relationship between HR and PPA was steeper in old vs young individuals (7.4% vs 5.3% each 10 bpm increase, p for slope difference = 0.02).
CONCLUSIONS:In our cohort, age is a significant effect-modifier of the relationship between HR and PPA. Ageing could be associated to more pronounced changes in PPA in response to HR changes. This may suggest a higher central hemodynamic load during low output states (e.g. during night or under the effect of HR-lowering drugs) in old vs young subjects.
OBJECTIVE:Anti-hypertensive drug classes may have differential effects on central (cBP) and peripheral (pBP) office BP, and consequently on their relationship, namely pressure amplification (PPA). We ...aimed at assessing the effect of anti-hypertensive treatment on PPA evaluated over the 24-hour period.
DESIGN AND METHOD:281 treated hypertensives (59 ± 14 years, 58% men) underwent ambulatory 24-hour cBP/pBP monitoring (ABPM) using the Mobil-o-Graph, a validated oscillometric brachial cuff-based sphygmomanometer which determines cBP from brachial oscillometric pressure waveforms by applying a proprietary generalized transfer function. PPA was calculated as pPP/cPP. Patients with history of severe valvulopathy and LV dysfunction, arrhythmias, peripheral obstructive atherosclerotic disease, or low-quality ABPMs (n.of readings <70% total) were excluded. Daytime and night-time intervals were calculated after removing intermediate shift hours (06.00–09.00 and 20.00–22.00 am).
RESULTS:31% of patients were treated with monotherapy, 36% with > = 3 drugs, 84% with ACE/ARBs. Mean 24-h PPA was 1.26 ± 0.07, mean daytime PPA (dPPA) was 1.31 ± 0.09, mean night-time PPA (nPPA) was 1.22 ± 0.07. Mean 24-h pBP was 128/78 ± 14/9 mmHg. In pairwise comparisons, subjects treated vs untreated with ACE/ARBs (60 ± 14 years vs 54 ± 15 years, p = 0.01), and with diuretics (63 ± 13 years vs 58 ± 14 years, p < 0.01), were older. Subjects treated with calcium-channel blockers (CCBs) were more frequently males (M = 67% vs 50%, p < 0.01), whereas individuals treated with β-blockers were more females (M = 46% vs 66%, p < 0.01), shorter (166 cm vs 170 cm, p < 0.01), and with significantly lower heart rate (HR 69 ± 9 bpm vs 71 ± 8 bpm, p < 0.01). In unadjusted comparisons, β-blockers were associated with lower 24-h PPA (1.24 vs 1.26, p = 0.04) and dPPA (1.29 vs 1.32, p < 0.01), whereas CCBs were associated with higher 24-h PPA (1.27 vs 1.25, p < 0.01). After adjustment for age, sex and height, β-blockers were only associated with lower dPPA (p = 0.02); such association, however, disappeared after further adjustment for HR (p = 0.49).
CONCLUSIONS:With the exception of β-blockers, all the anti-hypertensive drug classes have similar impact on 24-h PPA. The use of β-blockers is associated with reduced dPPA, which is mainly explained by the associated HR-lowering effect, but not with reduced nPPA. β-blockers may be responsible for an increased central hemodynamic load during daytime.
Hydrodynamic instabilities are usually investigated in confined geometries where the resulting spatiotemporal pattern is constrained by the boundary conditions. Here we study the Faraday instability ...in domains with flexible boundaries. This is implemented by triggering this instability in floating fluid drops. An interaction of Faraday waves with the shape of the drop is observed, the radiation pressure of the waves exerting a force on the surface tension held boundaries. Two regimes are observed. In the first one there is a coadaptation of the wave pattern with the shape of the domain so that a steady configuration is reached. In the second one the radiation pressure dominates and no steady regime is reached. The drop stretches and ultimately breaks into smaller domains that have a complex dynamics including spontaneous propagation.
Some classes of nematic liquid crystals can be driven through turbulent regimes when forced by an external electric field. In contrast to isotropic fluids, a turbulent nematic exhibits a transition ...to a stochastic regime that is characterised by a network of topological defects. We study the deformations arising after the electric field has been switched-off. In contrast to the turbulent regime, the relaxation of this topological-defect regime involves the annihilation of an interlacement of defect lines. We show that these defect lines separate regions of the nematic having topologically non-equivalent textures.
•State of art of management and treatment of hypertension emergency/urgency in Italy.•Good knowledge of definition and treatment.•Fair quality of blood pressure measurement technique.•Lack of ...protocol or fast track for this problem.•Differences in terms of treatment and diagnosis across macro-areas.
Hypertensive emergencies (HE) and urgencies (HU) are frequent causes of patients referral to Emergency Department (ED) and the approach may be different according to local clinical practice. Our aim was to explore awareness, management, treatment and counselling after discharge of HE and HU in Italy, by mean of an on-line survey. The young investigator research group of the Italian Society of Hypertension developed a 23-item questionnaire spread by e-mail invitation to the members of Italian Scientific societies in the field of Hypertension. 665 questionnaires were collected from EDs, Emergency and Urgency Medicine, Cardiology or Coronary Units, Internal Medicines, Intensive care, Stroke units. Symptoms considered suspicious of acute organ damage were: chest pain (89.0%), visual disturbances (89.8%), dyspnoea (82.7%), headache (82.1%), dizziness (52.0%), conjunctival haemorrhages (41.5%), tinnitus (38.2%) and epistaxis (34.4%). Exams more frequent prescribed were: electrocardiogram (97.2%), serum creatinine (91.4%), markers of cardiomyocyte necrosis (66.2%), echocardiography (65.1%). The use of intravenous or oral medications to treat HEs was 94.7% and 3.5%, while for HUs 24.4% and 70.8% respectively. Of note, a surprisingly high percentage of physicians (22 % overall, 24.5% in North Italy) used to prescribe sublingual nifedipine. After discharge, home blood pressure monitoring and general practitioner re-evaluation were more frequently suggested, while ambulatory blood pressure monitoring and hypertension specialist examination were less prescribed. The differences observed across the different macro-areas, regarded prescription of diagnostic test and drug administration. This survey depicts a complex situation of shades and lights in the real-life management of HE and HU in Italy.
Abstract Background and aim Morbid obesity is often accompanied by insulin resistance and increased ectopic fat surrounding the heart. We evaluated the relation of epicardial and pericardial fat with ...insulin resistance and left ventricular (LV) structure and function. Methods and results Epicardial and pericardial fat thicknesses were determined at 2-dimensional echocardiography in 80 morbid obese subjects age 42 ± 12 years, 31% men, body mass index (BMI) 44.4 ± 7 kg/m2 . LV hypertrophy (LV mass ≥51 g/m2.7 ), inappropriately high LV mass for a given cardiac workload (observed vs predicted LV mass >128%), and stress-adjusted LV mid-wall fractional shortening were determined. Pericardial and epicardial fat thicknesses had direct associations with BMI ( r = 0.40 and 0.45, both p < 0.01) and waist circumference ( r = 0.37 and 0.45, both p < 0.01). Pericardial (partial r = 0.35, p < 0.01), but not epicardial fat thickness (partial r = 0.05, p = n.s.), was correlated with homeostasis model assessment-insulin resistance after adjustment for BMI. Pericardial fat also had a strong negative correlation with mid-wall fractional shortening ( p = 0.01) and a positive one with inappropriately high LV mass ( p < 0.01), while no such relation was found for epicardial fat (both p = n.s.). Independently of age, male sex, BMI, and anti-hypertensive treatment, pericardial fat thickness had an independent positive association with inappropriately high LV mass ( β = 0.29, p = 0.02), and a negative one with stress-adjusted mid-wall fractional shortening ( β = −0.26, p = 0.04). Conclusions Pericardial fat thickness is associated with insulin resistance, inappropriately high LV mass, and LV systolic dysfunction in obese individuals. Findings from this study confirm the existence of a connection between insulin resistance, cardiac ectopic fat deposition and cardiac dysfunction in morbid obesity.
PDF
