1,528 research outputs found
Temperature Dependent Piezoelectric Properties of Lead-Free (1-x)K0.6Na0.4NbO3–xBiFeO3 Ceramics
(1-x)K0.4Na0.6NbO3–xBiFeO3 lead-free piezoelectric ceramics were successfully prepared in a single perovskite phase using the conventional solid-state synthesis. Relative permittivity (εr) as a function of temperature indicated that small additions of BiFeO3 not only broadened and lowered the cubic to tetragonal phase transition (TC) but also shifted the tetragonal to orthorhombic phase transition (TO–T) toward room temperature (RT). Ceramics with x = 1 mol.% showed optimum properties with small and large signal piezoelectric coefficient, d33 = 182 pC/N and d∗33 = 250 pm/V, respectively, electromechanical coupling coefficient, kp = 50%, and TC = 355°C. kp varied by ∼5% from RT to 90°C, while d∗33 showed a variation of ∼15% from RT to 75°C, indicating that piezoelectric properties were stable with temperature in the orthorhombic phase field. However, above the onset of TO–T, the properties monotonically degraded in the tetragonal phase field as TC was approached
A double-blind, randomized, comparative study of the use of a combination of uridine triphosphate trisodium, cytidine monophosphate disodium, and hydroxocobalamin, versus isolated treatment with hydroxocobalamin, in patients presenting with compressive neuralgias
CONTEXT: This paper reports on the results of treatment of compressive neuralgia using a combination of nucleotides (uridine triphosphate trisodium [UTP] and cytidine monophosphate disodium [CMP]) and vitamin B(12). OBJECTIVES: To assess the safety and efficacy of the combination of nucleotides (UTP and CMP) and vitamin B(12) in patients presenting with neuralgia arising from neural compression associated with degenerative orthopedic alterations and trauma, and to compare these effects with isolated administration of vitamin B(12). METHODS: A randomized, double-blind, controlled trial, consisting of a 30-day oral treatment period: Group A (n=200) receiving nucleotides + vitamin B(12,) and Group B (n=200) receiving vitamin B(12) alone. The primary study endpoint was the percentage of subjects presenting pain visual analog scale (VAS) scores ≤20 at end of study treatment period. Secondary study endpoints included the percentage of subjects presenting improvement ≥5 points on the patient functionality questionnaire (PFQ); percentage of subjects presenting pain reduction (reduction in VAS scores at study end in relation to pretreatment); and number of subjects presenting adverse events. RESULTS: The results of this study showed a more expressive improvement in efficacy evaluations among subjects treated with the combination of nucleotides + vitamin B(12), with a statistically significant superiority of the combination in pain reduction (evidenced by VAS scores). There were adverse events in both treatment groups, but these were transitory and no severe adverse event was recorded during the study period. Safety parameters were maintained throughout the study in both treatment groups. CONCLUSION: The combination of uridine, cytidine, and vitamin B(12) was safe and effective in the treatment of neuralgias arising from neural compression associated with degenerative orthopedic alterations and trauma
Airways oxidative stress, lung function and cognitive impairment in aging.
Abstract
BACKGROUND: An altered balance of oxidants/antioxidants is one of the pathological mechanisms of many age-dependent disorders. We aimed to investigate the age-related airways oxidative stress, using non invasive, safe and repeatable techniques; to evaluate the correspondence between systemic and local oxidative stress in healthy subjects of different age ranges; to analyse the correlation between systemic and local oxidative stress with lung function and with cognitive impairment.
METHODS: Thirty consecutive healthy high school graduated subjects (8 M, 22 F), divided in three ranges of age ( 60 years) were enrolled. All subjects underwent oxygen free radicals and exhaled nitric oxide measurement (by the diacron reactive oxygen metabolites test and by a rapid-response chemiluminescence nitric oxide analyzer), lung function tests, and cognitive impairment scales (Mini Mental State Examination and Geriatric Depression Scale).
RESULTS: A significant increase of oxygen free radicals, exhaled nitric oxide, and Geriatric Depression Scale score and a significant decrease of forced expiratory volume in 1 second and forced expiratory vital capacity from younger to older subjects were identified. Moreover, the significant positive correlation between oxygen free radicals and exhaled nitric oxide, and between oxygen free radicals and exhaled nitric oxide with Geriatric Depression Scale score were found. The significant negative correlation between forced expiratory volume in 1 second and oxygen free radicals or exhaled nitric oxide was also demonstrated.
CONCLUSIONS: Our data supports the role of progressive local oxidative stress in damaging the lung function and in inducing depression symptoms
long term outcomes following drug eluting stent implantation in unprotected left main bifurcation lesions
Background The safety and efficacy of drug-eluting stents (DES) implantation in unprotected left main (LM) bifurcation lesions has yet to be determined. The aim of the present report was to evaluate the long-term outcome following implantation of DES in unprotected LM bifurcation lesions. Methods We identified 70 consecutive patients treated with DES in unprotected LM bifurcation lesions from April 2003 to January 2005. Of them, 42 patients were treated with sirolimus-eluting stent (SES) and 28 patients were treated with paclitaxel-eluting stent (PES). Results Stents to the left anterior descending and to the circumflex were implanted in 62 patients. During 1-year follow-up, 3 (4.3%) patients died of cardiac causes. One of them had myocardial infarction and adjudicated as possibly due to stent thrombosis. Angiographic follow-up was available in 80% of patients. The per lesion restenosis rate was 13.4% in the entire cohort, of which 10.7% occurred in lesions treated with SES and 16.1% in those treated with PES (P=0.58). All restenosis was focal and occurred in the lesions treated with a stent with stent size to post-procedural reference vessel diameter ratio <1.0 (17.6% vs 0, P=0.04). The per patient target lesion revascularization rate at 1 year was 17.1%. One year survival free from major adverse cardiac events was 77.1%. Conclusions Treatment of LM bifurcation lesions using DES is a safe and feasible way with a low one-year mortality. The need for revascularization in 17% of patients demands for improvement
Exhaled Interleukine-6 and 8-isoprostane in chronic obstructive pulmonary disease: effect of carbocysteine lysine salt monohydrate (SCMC-Lys).
Chronic obstructive pulmonary disease (COPD) is characterized by an airways inflammation and by an enhanced generation of reactive oxygen species. The aim of our study was to assess the inflammation and the oxidative stress in airways of COPD patients with acute exacerbation of disease and in stability. Furthermore, we investigated the anti-inflammatory and antioxidant effects of 6 months treatment with carbocysteine lysine salt monohydrate (SCMC-Lys) in COPD. We studied 30 mild acute COPD, 10 mild stable COPD and 15 healthy subjects. 8-isoprostane and Interleukine-6 were measured in their breath condensate through immunoassay. Significantly higher concentrations of exhaled 8-isoprostane and Interleukine-6 were found in acute COPD patients compared to stable COPD and healthy controls (21.8+/-5.1 vs. 13.2+/-2.0 vs. 4.7+/-1.8 pg/ml and 7.4+/-0.9 vs. 5.8+/-0.2 vs. 2.7+/-0.6 pg/ml, p<0.0001). COPD patients treated with SCMC-Lys showed a marked reduction of exhaled 8-isoprostane and Interleukine-6 (8.9+/-1.5 and 4.6+/-0.8 pg/ml, p<0.0001). These findings suggest that there is an increase of 8-isoprostane and Interleukine-6 concentrations in the breath condensate of COPD patients compared to healthy controls especially during acute exacerbations of the disease. Moreover, we showed an anti-inflammatory and antioxidant effect of short-term administration of SCMC-Lys in COPD, suggesting the importance of a further placebo-controlled study that should evaluate the effects of this drug
Validity and reproducibility of morphologic analysis of nasal secretions obtained using ultrasonic nebulization of hypertonic solution.
BACKGROUND:
Collection of nasal secretions is important for the evaluation of upper airways inflammation in many nasal disorders.
OBJECTIVE:
To study the validity and reproducibility of nasal secretion cellularity induced by nebulization of hypertonic solution in patients with allergic rhinitis (AR), patients with nonallergic rhinitis with eosinophilia syndrome (NARES), and control subjects.
METHODS:
Sixty-eight individuals (29 with AR [mean +/- SD age, 33.3 +/- 16.9 years], 23 with NARES [mean +/- SD age, 46.4 +/- 16.6 years], and 16 controls [mean +/- SD age, 42.1 +/- 15.1 years]) underwent ultrasonic nebulization of hypertonic (4.5%) saline solution on 2 different occasions to study the validity and reproducibility of total and differential cell counts of nasal secretions.
RESULTS:
The mean +/- SD percentage of eosinophils was significantly higher in samples from patients with AR (20.8% +/- 23.1%) and NARES (18.7% +/- 22.8%) than in samples from controls (0.6% +/- 0.6%; P < .001 for both). There was a significant correlation between 2 samples of nasal secretions obtained on 2 different occasions for percentages of macrophages, neutrophils, eosinophils, and epithelial cells.
CONCLUSIONS:
The analysis of nasal secretions obtained using ultrasonic nebulization of hypertonic solution can distinguish patients with AR and NARES from controls. The reproducibility of this technique is good for macrophages, neutrophils, eosinophils, and epithelial cells. This method could be used to detect nasal airway inflammation in clinical settings
BiFeO3-BaTiO3: A new generation of lead-free electroceramics
Lead-based electroceramics such as Pb(Zr.Ti)O3 (PZT) and its derivatives have excellent piezoelectric, pyroelectric and energy storage properties and can be used in a wide range of applications. Potential lead-free replacements for PZT such as potassium sodium niobate (KNN) and sodium bismuth titanate (NBT) have a much more limited range of useful properties and have been optimized primarily for piezoelectric applications. Here, we review the initial results on a new generation of lead-free electroceramics based on BiFeO3-BaTiO3 (BF-BT) highlighting the essential crystal chemistry that permits a wide range of functional properties. We demonstrate that with the appropriate dopants and heat treatment, BF-BT can be used to fabricate commercially viable ceramics for applications, ranging from sensors, multilayer actuators, capacitors and high-density energy storage devices. We also assess the potential of BF-BT-based ceramics for electrocaloric and pyroelectric applications
Increased IL-6 and IL-4 in exhaled breath condensate of patients with nasal polyposis.
Abstract
BACKGROUND AND AIM: Nasal polyposis (NP) occurs in about 1-4% of the worldwide population. Increased plasma concentrations of different pro-inflammatory cytokines have been observed in NP, and might be related to the pathogenesis of this syndrome. The present study was designed to investigate IL-6 and IL-4 concentrations in nasal and oral exhaled breath condensate of patients with early and advanced NP, and following polypectomy.
METHODS: Ten individuals with polyposis in early status, twenty-three patients affected by advanced status of NP and ten healthy controls were enrolled into the study. Exhaled breath condensate was collected by all individuals, according to a previous standardised method. An immunoassay kit was used to measure IL-6 and IL-4 levels.
RESULTS: Concentrations of oral and nasal exhaled IL-6 and IL-4 were significantly higher in patients with early nasal polyposis and advanced nasal polyposis, compared to healthy controls. A statistically significant decrease of nasally but not of orally exhaled IL-6 (p < 0.001) and IL-4 (p < 0.05) was observed after polypectomy.
CONCLUSIONS: We consider oral and nasal exhaled condensate of IL-6 and IL-4 as valid inflammatory and oxidative stress marker in patients with nasal polyposis
High energy storage density and large strain in Bi(Zn2/3Nb1/3)O3-Doped BiFeO3-BaTiO3 ceramics
High recoverable energy density (Wrec ~ 2.1 J/cm3) was obtained in (0.7-x)BiFeO3-0.3BaTiO3-xBi(Zn2/3Nb1/3)O3 + 0.1wt% Mn2O3 (BF-BT-xBZN, x = 0.05) lead-free ceramics at < 200 kV/cm. Fast discharge speeds (< 0.5 μs), low leakage (~ 10-7 A/cm2) and small temperature variation in Wrec (~ 25% from 23 to 150 °C) confirmed the potential for these BiFeO3 based compositions for use in high energy density capacitors. A core-shell microstructure composed of a BiFeO3-rich core and BaTiO3-rich shell was observed by scanning and transmission electron microscopy which may contribute to the high value of energy density. In addition, for x = 0.005, a large electromechanical strain was observed with Spos = 0.463% and effective d33* ~ 424 pm/V, suggesting that this family of ceramics may also have potential for high strain actuators
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