162 research outputs found

    Hydrous hydrazine decomposition for hydrogen production using of ir/ceo2: Effect of reaction parameters on the activity

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    In the present work, an Ir/CeO2 catalyst was prepared by the deposition–precipitation method and tested in the decomposition of hydrazine hydrate to hydrogen, which is very important in the development of hydrogen storage materials for fuel cells. The catalyst was characterised using different techniques, i.e., X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with X‐ray detector (EDX) and inductively coupled plasma—mass spectroscopy (ICP‐MS). The effect of reaction conditions on the activity and selectivity of the material was evaluated in this study, modifying parameters such as temperature, the mass of the catalyst, stirring speed and concentration of base in order to find the optimal conditions of reaction, which allow performing the test in a kinetically limited regime

    Experimental and Process Modelling Investigation of the Hydrogen Generation from Formic Acid Decomposition Using a Pd/Zn Catalyst

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    The use of hydrogen as a renewable fuel has attracted great attention in recent years. The decomposition of formic acid under mild conditions was investigated using a 2%Pd6Zn4 catalyst in a batch reactor. The results showed that the conversion of formic acid increases with reaction temperature and with the formic acid concentration. A process-simulation model was developed to predict the decomposition of formic acid using 2%Pd6Zn4 in a batch reactor. The model demonstrated very good validation with the experimental work. Further comparisons between the 2%Pd6Zn4 catalyst and a commercial Pd/C catalyst were carried out. It was found that the 2%Pd6Zn4 demonstrated significantly higher conversions when compared with the commercial catalyst

    Experimental and process modelling investigation of the hydrogen generation from formic acid decomposition using a pd/zn catalyst

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    The use of hydrogen as a renewable fuel has attracted great attention in recent years. The decomposition of formic acid under mild conditions was investigated using a 2%Pd6Zn4 catalyst in a batch reactor. The results showed that the conversion of formic acid increases with reaction temperature and with the formic acid concentration. A process-simulation model was developed to predict the decomposition of formic acid using 2%Pd6Zn4 in a batch reactor. The model demonstrated very good validation with the experimental work. Further comparisons between the 2%Pd6Zn4 catalyst and a commercial Pd/C catalyst were carried out. It was found that the 2%Pd6Zn4 demonstrated significantly higher conversions when compared with the commercial catalyst

    Mono- and disubstituted-3,8-diazabicyclo[3.2.1]octane derivatives as analgesics structurally related to epibatidine: synthesis, activity, and modeling.

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    A series of 3,8-diazabicyclo[3.2.1]octanes substituted either at the 3 position compounds 1) or at the 8 position (compounds 2) by a chlorinated heteroaryl ring were synthesized, as potential analogues of the potent natural analgesic epibatidine. When tested in the hot plate assay, the majority of the compounds showed significant effects, the most interesting being the 3-(6-chloro-3-pyridazinyl)-3,8-diazabicyclo[3.2.1]octane (la). At a subcutaneous dose of 1 mg/kg, 1a induced a significant increase in the pain threshold, its action lasting for about 45 min. 1a also demonstrated good protection at a dose of 5 mg/kg in the mouse abdominal constriction test, while at 20 mg/kg it completely prevented the constrictions in the animals. Administration of naloxone (1 mg/kg ip) did not antagonize its antinociception while mecamylamine (2 mg/kg ip) did, thus suggesting the involvement of the nicotinic system in its action. Binding studies confirmed high affinity for the \u3b1\u3b22 nAChR subtype (K(i) = 4.1\ub10.21 nM). nAChR functional activity studies on three different cell lines showed that 1a was devoid of any activity at the neuromuscular junction. Finally, due to the analogy in their pharmacological profile with that of epibatidine, compounds were compared from a structural and conformational point of view through theoretical calculations and high-field 1H NMR spectroscopy. Results indicate that all of them present one conformation similar to that of epibatidine

    Biological and computational evaluation of an oxadiazole derivative (MD77) as a new lead for direct STAT3 inhibitors

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    Signal Transducer and Activator of Transcription 3 (STAT3) is a latent cytoplasmic protein overexpressed in various cancer cell lines. STAT3 participates in oncogenesis by stimulating cell proliferation and preventing apoptosis and it has been proven as a suitable target for anticancer therapy. In order to identify direct STAT3 inhibitors, we performed a binding assay on several previously synthesized 1,2,5-oxadiazole derivatives. Among them, compound MD77, N-[4-(4-chlorophenyl)-1,2,5-oxadiazol-3-yl]-4-(trifluoromethyl) benzamide, showed a good ability to bind the STAT3-SH2 domain in a dose-dependent manner (IC50 = 17.7 \u3bcM). Computational studies were carried out to investigate its binding mode. Moreover, compound MD77 showed a significant anti-proliferative activity versus several tumor cell lines. On these bases, compound MD77 was selected as a lead for the future development of direct STAT3 inhibitors

    Gender Related Differences in the Clinical Presentation of Hypertrophic Cardiomyopathy-An Analysis from the SILICOFCM Database

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    Background and Objectives: Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease that affects approximately 1 in 500 people. Due to an incomplete disease penetrance associated with numerous factors, HCM is not manifested in all carriers of genetic mutation. Although about two-thirds of patients are male, it seems that female gender is associated with more severe disease phenotype and worse prognosis. The objective of this study was to evaluate the gender related differences in HCM presentation. Materials and Methods: This study was conducted as a part of the international multidisciplinary SILICOFCM project. Clinical information, laboratory analyses, electrocardiography, echocardiography, and genetic testing data were collected for 362 HCM patients from four clinical centers (Florence, Newcastle, Novi Sad, and Regensburg). There were 33% female patients, and 67% male patients. Results: Female patients were older than males (64.5 vs. 53.5 years, p < 0.0005). The male predominance was present across all age groups until the age of 70, when gender distribution became comparable. Females had higher number of symptomatic individuals then males (69% vs. 52%, p = 0.003), most frequently complaining of dyspnea (50% vs. 30%), followed by chest pain (30% vs. 17%), fatigue (26% vs. 13%), palpitations (22% vs. 13%), and syncope (13% vs. 8%). The most common rhythm disorder was atrial fibrillation which was present in a similar number of females and males (19% vs. 13%, p = 0.218). Levels of N-terminal pro-brain natriuretic peptide were comparable between the genders (571 vs. 794 ng/L, p = 0.244). Echocardiography showed similar thickness of interventricular septum (18 vs. 16 mm, p = 0.121) and posterolateral wall (13 vs. 12 mm, p = 0.656), however, females had a lower number of systolic anterior motion (8% vs. 16%, p = 0.020) and other mitral valve abnormalities. Conclusions: Female patients are underrepresented but seem to have a more pronounced clinical presentation of HCM. Therefore, establishing gender specific diagnostic criteria for HCM should be considered

    are drug eluting stents superior to bare metal stents in patients with unprotected non bifurcational left main disease insights from a multicentre registry

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    Aims To compare long-term clinical outcome following drug-eluting stents (DES) or bare-metal stents (BMS) implantation on lesions located at the ostium or the shaft of the left main in a large real-world population. The advent of DES decreased the risk of unprotected left main coronary artery (ULMCA) restenosis when compared with BMS, but it is unclear if this advantage continues when non-bifurcational lesions are considered. Methods and results The GISE-SICI registry is a retrospective, observational multicentre registry promoted by the Italian Society of Invasive Cardiology in which 19 high-volume participating centres enrolled 1453 consecutive patients who underwent percutaneous coronary intervention on ULMCA between January 2002 and December 2006. From the registry, a total of 479 consecutive patients with ostial and shaft lesions who underwent DES ( n = 334) or BMS ( n = 145) implantation were analysed with extensive multivariable and propensity score adjustments. At 3-year follow-up, risk-adjusted survival rates were higher in patients treated with DES than in those treated with BMS. The adjusted hazard ratio (HR) for the risk of mortality after DES implantation relative to BMS implantation was 0.37 (95% CI: 0.15–0.96, P = 0.04). The adjusted HR for the risk of cardiac mortality was 0.31 (95% CI: 0.09–1.04, P = 0.06). The adjusted 3-year rates of target lesion revascularization (TLR) were not significantly lower in the DES group than in the BMS group ( P = 0.60). Conclusion In a large population of patients with lesions located at the ostium or the shaft of the left main in a real-world setting, DES were associated with favourable clinical outcomes when compared with BMS, although there was no evidence of a significant reduction in TLR with DES vs. BMS

    Genetic determinants of clinical phenotype in hypertrophic cardiomyopathy

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    BackgroundHypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disease that affects approximately one in 500 people. HCM is a recognized genetic disorder most often caused by mutations involving myosin-binding protein C (MYBPC3) and beta -myosin heavy chain (MYH7) which are responsible for approximately three-quarters of the identified mutations.MethodsAs a part of the international multidisciplinary SILICOFCM project (www.silicofcm.eu) the present study evaluated the association between underlying genetic mutations and clinical phenotype in patients with HCM. Only patients with confirmed single pathogenic mutations in either MYBPC3 or MYH7 genes were included in the study and divided into two groups accordingly. The MYBPC3 group was comprised of 48 patients (76%), while the MYH7 group included 15 patients (24%). Each patient underwent clinical examination and echocardiography.ResultsThe most prevalent symptom in patients with MYBPC3 was dyspnea (44%), whereas in patients with MYH7 it was palpitations (33%). The MYBPC3 group had a significantly higher number of patients with a positive family history of HCM (46% vs. 7%; p=0.014). There was a numerically higher prevalence of atrial fibrillation in the MYH7 group (60% vs. 35%, p=0.085). Laboratory analyses revealed normal levels of creatinine (85.518.3 vs. 81.3 +/- 16.4 mu mol/l; p=0.487) and blood urea nitrogen (10.2 +/- 15.6 vs. 6.9 +/- 3.9 mmol/l; p=0.472) which were similar in both groups. The systolic anterior motion presence was significantly more frequent in patients carrying MYH7 mutation (33% vs. 10%; p=0.025), as well as mitral leaflet abnormalities (40% vs. 19%; p=0.039). Calcifications of mitral annulus were registered only in MYH7 patients (20% vs. 0%; p=0.001). The difference in diastolic function, i.e. E/e ' ratio between the two groups was also noted (MYBPC3 8.8 +/- 3.3, MYH7 13.9 +/- 6.9, p=0.079).Conclusions Major findings of the present study corroborate the notion that MYH7 gene mutation patients are presented with more pronounced disease severity than those with MYBPC3
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