25 research outputs found
Pulmonary Hypertension in Dialysis Patients: A Cross-Sectional Italian Study
Introduction. Pulmonary hypertension (PHT) is an independent predictor of mortality. The aim of this study was to relate pulmonary arterial pressure (PAP) to the cardiovascular status of dialysis patients. Methods. 27 peritoneal dialysis (PD) and 29 haemodialysis (HD) patients (60 ± 13 years, 37 males, dialysis vintage was 40 ± 48 months) had PAP measured by echocardiography. Clinical and laboratory data of the patients were recorded.
Results. PHT (PAP > 35âmmHg) was detected in 22 patients (39%; PAP 42 ± 6âmmHg) and was diagnosed in 18.5% of PD patients and 58.6% of HD patients (P = .0021). The group of subjects with PH had higher dialysis vintage (63 ± 60 versus 27 ± 32 months, P = .016), interdialytic weight gain (2.1 ± 1 versus 1.3 ± 0.9âKg, P = .016), lower diastolic blood pressure (73 ± 12 versus 80 ± 8âmmHg, P = .01) and ejection fraction (54 ± 13 versus 60 ± 7%, P = .021) than the patients with normal PAP. PAP was correlated positively with diastolic left ventricular volume (r = 0.32, P = .013) and negatively with ejection fraction (r = â0.54, P < .0001). PHT was independently associated with dialysis vintage (OR 1.022, 95% CI 1.002â1.041, P = .029) and diastolic blood pressure (OR 0.861, 95% CI 0.766â0.967, P = .011). Conclusions. PHT is frequent in dialysis patients, it appears to be a late complication of HD treatment, mainly related to cardiac performance and cardiovascular disease history
Amiloidosi e Glomerulonefrite Extracapillare: un raro caso clinico di overlap
L'amiloidosi Ăš una malattia caratterizzata dalla deposizione in sede extracellulare di materiale di natura proteica detto amiloide. Questa malattia sistemica puĂČ essere sia primitiva AL che secondaria AA. Il coinvolgimento renale Ăš un'evenienza frequente e, occasionalmente, si assiste a un'insufficienza renale rapidamente progressiva sostenuta dalla sovrapposizione di una glomerulonefrite extracapillare. I rari casi riportati in letteratura sono correlati a un'amiloi-dosi secondaria all'artrite reumatoide.
Si riporta il caso clinico di una donna di 46 anni tabagista, affetta da ipotiroidismo su base autoimmune, giunta alla nostra osservazione per la comparsa di sindrome nefrosica, ipertensione arteriosa, anemizzazione e insufficienza renale acuta. L'esame bioptico renale evidenziava un quadro compatibile con la presenza contemporanea di amiloidosi primitiva AL e glomerulonefrite extracapillare. Nonostante l'avvio tempestivo della terapia farmacologica, la paziente Ăš deceduta dopo circa sei mesi
UVES analysis of red giants in the bulge globular cluster NGC 6522
Context. NGC 6522 is a moderately metal-poor bulge globular cluster ([Fe/H] ~ â1.0), and it is a well-studied representative among a number of moderately metal-poor blue horizontal branch clusters located in the bulge. The NGC 6522 abundance pattern can give hints on the earliest chemical enrichment in the central Galaxy. Aims. The aim of this study is to derive abundances of the light elements C and N; alpha elements O, Mg, Si, Ca, and Ti; odd-Z elements Na and Al; neutron-capture elements Y, Zr, Ba, La, and Nd; and the r-process element Eu. We verify if there are first- and second-generation stars: we find clear evidence of NaâAl, NaâN, and MgâAl correlations, while we cannot identify the NaâO anti-correlation from our data. Methods. High-resolution spectra of six red giants in the bulge globular cluster NGC 6522 were obtained at the 8m VLT UT2-Kueyen telescope with both the UVES and GIRAFFE spectrographs in FLAMES+UVES configuration. In light of Gaia data, it turned out that two of them are non-members, but these were also analysed. Spectroscopic parameters were derived through the excitation and ionisation equilibrium of Fe I and Fe II lines from UVES spectra. The abundances were obtained with spectrum synthesis. Comparisons of abundances derived from UVES and GIRAFFE spectra were carried out. Results. The present analysis combined with previous UVES results gives a mean radial velocity of vrhel = â15.62±7.7 km sâ1 and a metallicity of [Fe/H] = â1.05 ± 0.20 for NGC 6522. Mean abundances of alpha elements for the present four member stars are enhanced with [O/Fe] = +0.38, [Mg/Fe] = â+0.28, [Si/Fe] â +0.19, and [Ca/Fe] â +0.13, together with the iron-peak element [Ti/Fe] â +0.13, and the r-process element [Eu/Fe] = +0.40. The neutron-capture elements Y, Zr, Ba, and La show enhancements in the +0.08 < [Y/Fe] < +0.90, 0.11 < [Zr/Fe] < +0.50, 0.00 < [Ba/Fe] < +0.63, 0.00 < [La/Fe] < +0.45, and â0.10 < [Nd/Fe] < +0.70 ranges. We also discuss the spread in heavy-element abundances
RIGED-RA project - Restoration and management of Coastal Dunes in the Northern Adriatic Coast, Ravenna Area - Italy
Coastal dunes play an important role in protecting the coastline. Unfortunately, in the last decades dunes have been removed or damaged by human activities. In the Emilia- Romagna region significant residual dune systems are found only along Ravenna and Ferrara coasts. In this context, the RIGED-RA project "Restoration and management of coastal dunes along the Ravenna coast" (2013-2016) has been launched with the aims to identify dynamics, erosion and vulnerability of Northern Adriatic coast and associated residual dunes, and to define intervention strategies for dune protection and restoration. The methodology is based on a multidisciplinary approach that integrates the expertise of several researchers and investigates all aspects (biotic and abiotic), which drive the dune-beach system. All datasets were integrated to identify test sites for applying dune restoration. The intervention finished in April 2016; evolution and restoration efficiency will be assessed
Maintaining over time Clinical Performance targets on Anaemia correction in unselected population on chronic dialysis at 20 Italian Centres. Data from a retrospective study for a Clinical Audit
<p>Abstract</p> <p>Background</p> <p>The Italian and European Best Practice Guidelines (EBPG) recommend a target haemoglobin value greater than 11 g/dl in most patients with Chronic Kidney Diseases. However, it is still difficult to maintain these values at a steady rate. Thus, the main aim of the study was to evaluate, throughout 2005, how many patients steadily maintained the performance targets related to anaemia treatment.</p> <p>Methods</p> <p>The survey was conducted on 3283 patients on haemodialysis (HD) and peritoneal dialysis (PD) at 20 Italian dialysis centres. 540 patients were randomly selected; each centre provided a statistically significant sample proportional to its total number of patients. Maintenance of the following target levels was assessed over time: Haemoglobin (HB) 11-12 gr/dl; Iron: 60-160 mcg/dl; Ferritin: 30-400 mcg/l; Transferrin: 200-360 mg/dl; Transferrin saturation percentage (TSAT %):> 25 <50; Dialysis doses (KT/V): >1.2 <2.0 for non-diabetic HD patients; >1.5 <2.2 for diabetic HD patients; DP: >1.8 <2.5.</p> <p>Outcome included:</p> <p indent="1">1- Percentage of target maintenance for each parameter.</p> <p indent="1">2- Erythropoietin dose in relation to dialysis techniques, presence of cancer or myeloma, diabetic status, Vitamin B therapy.</p> <p indent="1">3- Erythropoietin dose (International Units/kg/week) (IU/kg/wk) depending on: haemoglobin values, hospitalization of more than 3 days.</p> <p>Results</p> <p>Mean age was 65.1; mean haemoglobin concentration over the whole population was 11.3 gr/dl (Standard Deviation (SD): 0.91). The clinical performance targets were maintained over time as follows: HB: 4.3% (Mean 11.43 gr/dl) (SD: 0.42); Ferritin: 71.1% (Mean: 250.23 mcg/L (SD:104.07); Iron: 95.0% (Mean 59.79 mcg/dl)(SD:16.76); Transferrin: 44.8% (Mean 216.83 mg/dl) (SD: 19,50); TSAT %: in 8.4% (Mean: 34.33% (SD: 6.56); HD KT/V: 61.0% (Mean:1.46) (SD: 0.7); PD KT/V:31.4% (Mean: 2.10) (SD: 0.02). The average weekly dose of Erythropoietin (IU/Kg/Wk) was significantly lower for the peritoneal dialysis technique; the higher haemoglobin values, the lower the Erythropoietin dose (IU/Kg/Wk).</p> <p>Conclusion</p> <p>A very low percentage of patients maintained haemoglobin target values over time. We need to identify precise criteria to evaluate the stability over time of clinical performance targets proposed by the guidelines.</p
Experimental stability analysis of tractor drivelines affected by cold judder
Clutch judder is a friction-generated self-excited vibration affecting automotive drivelines. Stick-slip, negative gradient of the friction coefficient and geometric disturbances are the only causes currently identified in the scientific literature. Nevertheless, they are not sufficient to explain the vibration occurring in drivelines (typically of tractors) with dither (oscillating component) added to clutch hydraulic actuation signals. In this study, experimental data acquired on a specifically designed test bench are processed to show that this particular kind of judder is an instability due to parametrical excitation exerted by the actuation pressure signal. A minimal model with four degrees of freedom is proposed, able to fit the experimental data, to explain the onset of the parametrically excited vibration, and to identify which parameters have a major role in controlling this phenomenon. Stability charts obtained from the proposed model also represent a useful tool to prevent instability already in the design phase
Friction-induced parametric oscillations in automotive drivelines: experimental analysis and modelling
Clutch judder is a friction-induced self-excited vibration occurring in automotive drivelines, an NVH issue studied for more than forty years and attributed by the scientific community to three possible causes: stick-slip, negative gradient of the coefficient of friction and geometric disturbances. However, these explanations fail to describe the kind of judder studied in this contribution, arising in presence of an oscillating component (dither) in the clutch actuation pressure. The analysis of experimental data collected on a dual-clutch transmission mounted on a specific test bench suggested the presence of a parametric resonance, generated by the dither. A specific 4 degrees of freedom model was then developed, able to predict with good accuracy the unstable parametric region in which judder occurs and useful in the design stage
Modeling the meander morphodynamics with internal boundary conditions given by a localized variation in the flow field
Modeling of long-term evolution of meander planforms is usually applied to river reaches characterized by a uniform flow perturbed by the effects of the curvature and width distributions. However, in nature meandering rivers may be characterized by localized variations due to external conditions, e.g. changes in floodplain slope (geologic variation), confluence of a tributary into the main river (hydrologic variation), or backwater effects (hydrodynamic variation). As a consequence, the hypothesis of a sufficiently long reach having constant forcing characteristic could limit the reliability of the numerical simulations. We developed a mathematical extension of a well-known fully coupled two-dimensional morphodynamic model (i.e., the ZS model) able to manage an internally localized boundary condition which affects the characteristic of the main flow. The resulting modular model computes the flow field in the two meandering sub-reaches determined by the presence of a section entailing prescribed changes in external conditions, and simulates the long-term lateral migration above the floodplain surface due to erosion and deposition processes at the banks, and the possible occurrence of neck cutoffs. Calibration runs and simulations based on real test cases show that internal variations in the parameters controlling the flow field might strongly affect the morphodynamic behavior of the migrating planforms. Future research shall provide an extension of this approach in order to manage multiple internal boundary conditions within the investigated river reach. The aim is to relax the common hypothesis of a unique formative uniform flow, exploiting the less restrictive assumption of a sequence of uniform flows to describe the flow field that establishes in the river and controls its morphodynamic behaviour