For applications benefitting from the swelling properties of nanolayered silicates (clay minerals), it is of paramount importance to understand the hysteresis in the clay–water interaction. In this ...context, the present work investigates how the thermal history of Na+- and Li+-intercalated fluorohectorite affects the hydration process. By combining X-ray diffraction and thermogravimetric analysis, water adsorption of preheated and non-preheated fluorohectorite was measured and analyzed in terms of the characteristic interlayer distance. The number of water molecules per cation was also inferred. We find that some of the hydration states in preheated samples are suppressed, and transitions to higher hydration states are achieved at higher relative humidity values. This could be due to the initial water content that facilities crystalline swelling. However, the data for Li-fluorohectorite do not exclude the possibility of a low temperature Hofmann–Klemen effect at 150 °C. Our study also provides strong hints that the so-called 1.5 water layer state, observed in previous studies on smectites, is a metastable state. In addition, the impact of a hydrogenous structure in the interlayer space of Li-fluorohectorite on the clay’s hydration behavior is demonstrated. The results, if generalized, would have strong implications on a wide range of applications, where the thermal history of smectites is important.
OBJECTIVE:Serum uric acid (SUA) is a predictor of cardiovascular disease (CVD), but its levels that discriminate risk for CVD and mortality remain unknown. We used a large Italian population ...comprising >30000 subjects to assess the threshold of SUA that increases the risk of total and CVD mortality.
DESIGN AND METHOD:The URic Acid Right for heArt Health (URRAH) study is a regional-basis multicentre cohort study collecting data from prospective studies and databases from different hypertension centres. Total mortality included mortality for any causes, cardiovascular mortality as death due to fatal myocardial infraction, stroke or heart failure. Multivariate dichotomic logistic and Cox regression models were used to confirm the relationship between SUA and mortality both from cardiovascular and any causes, while ROC curves were used to identify the threshold of SUA that better discriminated people at higher or lower mortality risk.
RESULTS:22.275 subjects had SUA and mortality information. Logistic regression identified a direct and strong association between SUA and an increased risk of total (OR 1.176, 95%CI 1.127–1.227) and CVD (OR 1.147, 95%CI 1.093–1.203) mortality, independently of other confounders. Cox models confirmed an independent association between SUA and any causes, and CVD mortality. ROC curve analysis identified a cut-off value od SUA (4.79 mg/dL (95%CI 4.7–5.4 mg/dl) able to discriminate total mortality status, and a different one (5.60 mg/dL (95%CI 5.09–5.89 mg/dl) able to identify CVD mortality status. Multivariate Cox analysis adjusted for confounders confirmed that subjects with SUA >4.79 mg/dl had a significantly higher total mortality (HR 1.293, 95%CI 1.181–1.416) compared to those with SUA < 4.79 mg/dl. Similarly, subjects with SUA >5.60 mg/dl had a significantly higher CVD mortality (HR 1.428, 95%CI 1.273–1.600) than those with SUA < 5.60 mg/dl after adjustment for the same confounders.
CONCLUSIONS:Levels of SUA that increase the risk of total and CVD mortality are significantly lower than those commonly used for the definition of hyperuricemia in clinical practice. Our data provide the first large evidence of a level of “cardiovascular” SUA that might be used in clinical practice to identify subjects at greater risk of total and CVD mortality.
OBJECTIVE:The aim of this study was to evaluate the influence of gender on left ventricular (LV) mechanics in hypertensive individuals.
DESIGN AND METHOD:This cross-sectional study included 198 ...untreated hypertensive subjects and 107 normotensive controls who underwent 24-hour ambulatory blood pressure monitoring and comprehensive two-dimensional echocardiographic examination including strain assessment.
RESULTS:There was no difference in 24-h blood pressure between hypertensive men and women. LV mass index was significantly higher men than in women in hypertensive and normotensive group. Hypertensive men and women had significantly lower 2D LV global longitudinal, circumferential and radial strains than their normotensive counterparts. LV global longitudinal strain was lower in hypertensive men than in women (−20.2 ± 2.3 vs. −18.8 ± 2.0, p < 0.01). LV global circumferential strain was also worse in hypertensive men than in men (−21.4 ± 2.9 vs. −19.5 ± 2.5, p < 0.01). The difference in LV radial strain was not discovered between hypertensive women and men. Assessment of layer-specific LV strain showed that endocardial and mid-myocardial longitudinal and circumferential strains were significantly lower in hypertensive population and especially in hypertensive men comparing with hypertensive women. Furthermore, LV twist was significantly higher in hypertensive women than in hypertensive men (20.6 ± 6.8 degree vs. 21.6 ± 7.3 degree, p = 0.02). Female gender and arterial hypertension, as well as their interaction, were associated with LV hypertrophy, reduced LV global longitudinal strain and increased LV twist.
CONCLUSIONS:LV longitudinal and circumferential strains were significantly reduced in hypertensive patients. Endo- and mid-myocardial LV layers were particularly influenced by arterial hypertension. However, hypertensive women suffered more significant changes in LV longitudinal strain and LV twist than hypertensive men.
summary The electromyographic (EMG) characteristics of masseter, temporalis and sternocleidomastoid (SCM) muscles during maximum voluntary teeth clench were assessed in 27 male and 35 female healthy ...young adults. Subjects were divided into two groups: (i) ‘complete’ Angle Class I (bilateral, symmetric canine and molar Class I relationships), and (ii) ‘partial’ Angle Class I (one to three canine/molar Class I relationships, the remaining relationships were Class II or Class III). On average, standardized muscular symmetry ranged 80·7–87·9%. During maximum voluntary teeth clench, average co‐contraction of SCM muscle was 13·7–23·5% of its maximum contraction. On average, all torque coefficients (potential lateral displacing component) were >90%, while all antero‐posterior coefficients (relative activities of masseter and temporalis muscles) were >85%. The average integrated areas of the masseter and temporalis EMG potentials over time ranged 87·4–106·8 μV/μV s%. Standardized contractile muscular activities did not differ between ‘complete’ and ‘partial’ Angle Class I, and between sexes (two‐way analysis of variance). A trend toward a larger intragroup variability in EMG indices was observed in the subjects with ‘partial’ Angle Class I than in those with ‘complete’ Angle Class I (significant difference for the temporalis muscle symmetry, P = 0·013, analysis of variance). In conclusion, the presence of a complete or partial Angle occlusal Class I did not seem to influence the standardized contractile activities of masseter, temporalis and SCM muscles during a maximum voluntary clench. Subjects with a ‘complete’ Angle Class I were somewhat a more homogenous group than subjects with ‘partial’ Angle Class I.
OBJECTIVE:We aimed to evaluate the functional capacity and left ventricular (LV) mechanics, as well as their relationship in the patients with uncomplicated type 2 diabetes.
DESIGN AND METHOD:This ...cross-sectional observational study included 70 controls and 60 patients with uncomplicated diabetes. Included subjects underwent laboratory analysis, cardiopulmonary exercise testing and comprehensive echocardiographic examination.
RESULTS:Oxygen uptake at ventilatory threshold (18.8 ± 3.8 vs. 14.8 ± 3.7 ml/kg/min, p < 0.001), peak oxygen uptake (peak VO2) (28.2 ± 4.2 vs. 19.8 ± 4.4, ml/kg/min, p < 0.001) and oxygen pulse (13.8 ± 2.9 vs. 11.3 ± 3.1 ml/beat, p < 0.001) were significantly lower in the diabetic group, whereas ventilation/carbon dioxide ratio and ventilation/carbon dioxide slope (25.0 ± 2.4 vs. 28.2 ± 3.7, p < 0.001) were significantly higher in this group. Longitudinal, circumferential and radial strains were significantly lower in the diabetic patients than in healthy controls (−21.6 ± 2.9 vs. −18.1 ± 2.2 %, p < 0.001; −22 ± 2.6 vs. −18.6 ± 2.7 %, p < 0.001; 39.4 ± 9.3 vs. 35.5 ± 8.8 %, p < 0.001, respectively). A multivariate regression analysis showed that HbA1c, mitral E/e ratio and peak VO2 were associated with LV longitudinal and circumferential strains independently of age, BMI, systolic blood pressure and LV mass index in the whole study population.
CONCLUSIONS:Our investigation showed that both, functional capacity and LV mechanics were significantly impaired in the uncomplicated diabetic patients. HbA1c, the essential parameter of glucose regulation, LV diastolic function and oxygen consumption were independently associated with LV mechanics in the whole study population. This shows an important role of functional capacity as important markers of preclinical cardiac damage in diabetic population.
Previous studies have shown that alterations in vascular, metabolic, inflammatory and haemocoagulative functions characterise the metabolic syndrome. Whether this is also the case for sympathetic ...function is not clear. We therefore aimed to clarify this issue and to determine whether metabolic or reflex mechanisms might be responsible for the possible adrenergic dysfunction.
In 43 healthy control subjects (age 48.2+/-1.0 years, mean+/-SEM) and in 48 untreated age-matched subjects with metabolic syndrome (National Cholesterol Education Program's Adult Treatment Panel III Report criteria) we measured, along with anthropometric and metabolic variables, blood pressure (Finapres), heart rate (ECG) and efferent postganglionic muscle sympathetic nerve activity (microneurography) at rest and during baroreceptor manipulation (vasoactive drug infusion technique).
Compared with control subjects, subjects with metabolic syndrome had higher BMI, waist circumference, blood pressure, cholesterol, triglycerides, insulin and homeostasis model assessment (HOMA) index values but lower HDL cholesterol values. Sympathetic nerve traffic was significantly greater in subjects with metabolic syndrome than in control subjects (61.1+/-2.6 vs 43.8+/-2.8 bursts/100 heartbeats, p<0.01), the presence of sympathetic activation also being detectable when the metabolic syndrome did not include hypertension as a component. Muscle sympathetic nerve traffic correlated directly and significantly with waist circumference (r=0.46, p<0.001) and HOMA index (r=0.49, p<0.001) and was inversely related to baroreflex sensitivity (r=-0.44, p<0.001), which was impaired in the metabolic syndrome.
These data provide evidence that the metabolic syndrome is characterised by sympathetic activation and that this abnormality (1) is also detectable when blood pressure is normal and (2) depends on insulin resistance as well as on reflex alterations.
Overviewing the European carbon (C), greenhouse gas (GHG), and non-GHG fluxes, gross primary productivity (GPP) is about 9.3 Pg yr⁻¹, and fossil fuel imports are 1.6 Pg yr⁻¹. GPP is about 1.25% of ...solar radiation, containing about 360 x 10¹⁸ J energy - five times the energy content of annual fossil fuel use. Net primary production (NPP) is 50%, terrestrial net biome productivity, NBP, 3%, and the net GHG balance, NGB, 0.3% of GPP. Human harvest uses 20% of NPP or 10% of GPP, or alternatively 1per thousand of solar radiation after accounting for the inherent cost of agriculture and forestry, for production of pesticides and fertilizer, the return of organic fertilizer, and for the C equivalent cost of GHG emissions. C equivalents are defined on a global warming potential with a 100-year time horizon. The equivalent of about 2.4% of the mineral fertilizer input is emitted as N₂O. Agricultural emissions to the atmosphere are about 40% of total methane, 60% of total NO-N, 70% of total N₂O-N, and 95% of total NH₃-N emissions of Europe. European soils are a net C sink (114 Tg yr⁻¹), but considering the emissions of GHGs, soils are a source of about 26 Tg CO₂ C-equivalent yr⁻¹. Forest, grassland and sediment C sinks are offset by GHG emissions from croplands, peatlands and inland waters. Non-GHGs (NH₃, NOx) interact significantly with the GHG and the C cycle through ammonium nitrate aerosols and dry deposition. Wet deposition of nitrogen (N) supports about 50% of forest timber growth. Land use change is regionally important. The absolute flux values total about 50 Tg C yr⁻¹. Nevertheless, for the European trace-gas balance, land-use intensity is more important than land-use change. This study shows that emissions of GHGs and non-GHGs significantly distort the C cycle and eliminate apparent C sinks.
OBJECTIVEWe sought to perform a comprehensive assessment of long-term changes in left ventricular (LV) mass, focusing on new onset, persistence, regression and severity of LV hypertrophy (LVH), as ...well as independent demographic and clinical variables related to this dynamic process in a population-based sample.
DESIGN AND METHODA total of 1,113 participants with measurable echocardiographic parameters at baseline evaluation and at the end of a ten-year follow-up period were included in the present analysis. Cut-points for LVH were derived from current echocardiographic guidelines
RESULTSLVH prevalence significantly increased from 13% to 33%, as a consequence of new onset LVH in 254 and regression in 31 cases, respectively. Severe LVH increased about 1.8 times as compared to baseline and this trend was mainly related to the transition from mild and moderate to severe LVH in subjects with pre-existing cardiac hypertrophy. A number of baseline variables such as age, female gender, office and out-of-office systolic BP, body mass index, ATP 3 metabolic syndrome, and use of antihypertensive drugs were independently correlated either to new-onset and persistent LVH.
CONCLUSIONSLong-term LV mass changes in the general population are associated to a marked worsening in cardiovascular risk profile related to increased prevalence and severity of LVH. As BP, metabolic variables and BMI emerged as key correlates of a such dynamic process, our findings suggest that early interventions aimed to modify such risk factors at the community level may have a role in preventing new onset and progression LVH.
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