Cerium oxide/multiwalled carbon nanotube composites with different oxide loadings (5–60wt. %) were prepared by sol-gel deposition of the oxide onto the carbon support. The morphology, texture and ...surface properties of the prepared materials were studied and correlated with their electrochemical behavior. The different charge storage mechanisms occurring on the surface of the composites were successfully identified by a newly developed electrochemical method, namely the combination of sweep wave voltammetry with deconvolution analysis in 1M H2SO4. The deposition of moderate oxide loadings (up to 10wt. %) leads to small and well distributed oxide particles on the nanotubes surface. Therefore, the appearance of defects on the oxide structure is favored, promoting both electronic conduction and faradaic activity. Curiously, cerium oxide loadings above 10wt. % induce a higher dispersion of the carbon support. This convenient synergism enhances the electroactive area of the composites by increasing molecular diffusion.
Hierarchical ordered porous carbons show a better behavior as electric double layer capacitors (EDLCs) than disordered carbons especially at high rates thanks to their unique architectural design. In ...the present work, we demonstrate that mesostructural order is a key factor for the performance of carbons at high rates. For that, two series of hierarchical micro–mesoporous carbons were prepared by chemical activation with KOH following two different procedures. SBA-15 silica was infiltrated by chemical vapor deposition of propylene and the resulting carbon–silica composite was split into two halves. One part was directly activated and, subsequent to the activation process, the template was eliminated. The second part was first subjected to the template removal and the resulting CMK-3 type carbon was further activated. Thus, carbons obtained by both these methods present bimodal pore size distributions and different mesostructural order as a function of the activation conditions. Carbons prepared from the direct activation of the composite present a high conservation of the ordered mesoporous structure. The electrochemical performance of both carbon series was tested in an acid aqueous electrolyte (1 M H 2 SO 4 ) by cyclic voltammetry and impedance spectroscopy. A highly ordered mesoporous structure significantly improves the specific capacitance at high scan rates due to enhancement in the diffusion of molecules.
Abstract Objective ABI is a good predictor of morbidity and motality in diabetic subjects with no known cardiovascular disease. However, its prognostic value in diabetic patients with prior coronary ...or cerebrovascular disease has not previously been evaluated. Methods Multicenter, prospective study of 1 year of follow-up, in 1096 patients (73.6 years, 65% males, 45.4% with diabetes) with cardiovascular disease and without known peripheral arterial disease. The main outcome measure was the first occurrence of a major cardiovascular event (non-fatal acute coronary syndrome, non-fatal stroke, revascularization procedure, or cardiovascular death). Secondary endpoints included major cardiovascular events, cardiovascular death and death from any cause. Results Prevalence of an abnormal ABI (<0.9 or >1.4) was 38.2% in diabetic and 26.8% in non-diabetic subjects. There were 150 major cardiovascular events (38.3/1000 person-years in diabetics vs. 30.6/1000 person-years in non-diabetics subjects, p = 0.012) and 60 cardiovascular deaths (11.8/1000 person-years in diabetics vs. 10.7/1000 person-years in non-diabetics subjects, p = 0.156). Patients with abnormal ABI had a higher rate of vascular complications. There was a significant interaction between ABI and diabetes. In non-diabetic patients, an abnormal ABI was associated with an increase risk of the primary endpoint (HR 2.71; 95% CI 1.54–4.76), cardiovascular mortality (HR 4.62; 95% CI 1.47–14.52) and total mortality (HR 2.80; 95% CI 1.08–7.27). These associations were not observed in patients with diabetes. Conclusion In patients with cardiovascular disease, ABI is a good predictor of risk of recurrent cardiovascular events and death, only in non-diabetic subjects.
Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly ...desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g., adenosine monophosphate) as bifunctional agents for the electrochemical exfoliation and dispersion of graphene nanosheets in water. Acting both as exfoliating electrolytes and colloidal stabilizers, these biomolecules facilitated access to aqueous graphene bio-inks that could be readily processed into aerogels and inkjet-printed interdigitated patterns. Na-O2 batteries assembled with the graphene-derived aerogels as the cathode and a glyme-based electrolyte exhibited a full discharge capacity of ∼3.8 mAh cm–2 at a current density of 0.2 mA cm–2. Moreover, shallow cycling experiments (0.5 mAh cm–2) boasted a capacity retention of 94% after 50 cycles, which outperformed the cycle life of prior graphene-based cathodes for this type of battery. The positive effect of the nucleotide-adsorbed nanosheets on the battery performance is discussed and related to the presence of the phosphate group in these biomolecules. Microsupercapacitors made from the interdigitated graphene patterns as the electrodes also displayed a competitive performance, affording areal and volumetric energy densities of 0.03 μWh cm–2 and 1.2 mWh cm–3 at power densities of 0.003 mW cm–2 and 0.1 W cm–3, respectively. Taken together, by offering a green and straightforward route to different types of functional graphene-based materials, the present results are expected to ease the development of novel energy storage technologies that exploit the attractions of graphene.
Abstract Aim To determine the effect of the type of mutation in low-density lipoprotein receptor gene and the risk factors associated with the development of premature cardiovascular disease (PCVD) ...in a large cohort of heterozygous familial hypercholesterolemia (hFH) subjects with genetic diagnosis in Spain. Methods and results A cross-sectional study was conducted on 811 non-related FH patients (mean age 47.1 ± 14 years, 383 males and 428 females) with a molecular defect in the low-density lipoprotein receptor ( LDLR ) gene from the Spanish National FH Register. Prevalence of PCVD was 21.9% (30.2% in males and 14.5% in women, P < 0.001). Mean age of onset of cardiovascular event was 42.1 years in males and 50.8 years in females. Of those patients with PCVD, 59.5% of males and 27% of females suffered a second cardiovascular (CV) event. In multivariate analysis male gender, age, tobacco consumption (ever), and total cholesterol/HDL-cholesterol (TC/HDL-C) ratio were significantly associated with PCVD. Two hundred and twenty different mutations were found with a large heterogeneity. Patients carrying null-mutations had significantly higher frequency of PCVD and recurrence of CV events. No relationship with Lp(a) levels and genotype of Apo E were found. Conclusions This study confirms the importance of identifying some classic risk factors such as smoking and TC/HDL-C ratio, and also the type of mutation in LDLR gene in order to implement early detection and intensive treatment for the prevention of cardiovascular disease in FH patients.
A generic expression to compute triple parton scattering cross sections in high-energy proton-proton (pp) collisions is presented as a function of the corresponding single parton cross sections and ...the transverse parton profile of the proton encoded in an effective parameter σ_{eff,TPS}. The value of σ_{eff,TPS} is closely related to the similar effective cross section that characterizes double parton scatterings, and amounts to σ_{eff,TPS}=12.5±4.5 mb. Estimates for triple charm (ccover ¯) and bottom (bbover ¯) production in pp collisions at LHC and FCC energies are presented based on next-to-next-to-leading-order perturbative calculations for single ccover ¯, bbover ¯ cross sections. At sqrts≈100 TeV, about 15% of the pp collisions produce three ccover ¯ pairs from three different parton-parton scatterings.
•Phosphorous functionalized graphene samples are developed•Solid state NMR proves two different phosphorous species related to the temperature treatment•Charge storage is improved by prior ...electrochemical activation in 1 M H2SO4 electrolyte•No capacitance loss after 60,000 charge discharge cycles at 1.5 V
The mechanisms behind enhanced charge storage of P-functionalized carbons are unraveled for the first time using non-porous graphene oxide treated with phosphoric acid and annealed at either 400 or 800 °C. The electrochemical study in 1 M H2SO4 reveals that phosphorus groups boost charge storage and electrochemical stability, with more effect for the higher annealing temperature. Annealing at 800 °C also leads to the material withstanding 60,000 charge-discharge cycles with no capacitance loss at 1.5 V. The improvement in the electrochemical performance is shown to be mainly governed by the change in surface chemistry comprehensively studied with NMR, FTIR and XPS characterization techniques. The collective analysis of electrochemical response and surface chemistry demonstrates that enhanced charge storage by phosphorus-functionalized graphene materials is made possible due to the following synergistic mechanisms: i) non-Faradaic charging; ii) nascent hydrogen storage in the interlayer; iii) benzoquinone-to-hydroquinone redox processes; iv) phosphate-to-phosphonate like transformation. From the practical perspective, the stored charge can be boosted due to the higher capacitance upon prior electrochemical activation in the vicinity of oxygen evolution potential and the wider usable electrochemical window enabled by phosphorus-related groups.
Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly ...desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g., adenosine monophosphate) as bifunctional agents for the electrochemical exfoliation and dispersion of graphene nanosheets in water. Acting both as exfoliating electrolytes and colloidal stabilizers, these biomolecules facilitated access to aqueous graphene bio-inks that could be readily processed into aerogels and inkjet-printed interdigitated patterns. Na-O
batteries assembled with the graphene-derived aerogels as the cathode and a glyme-based electrolyte exhibited a full discharge capacity of ∼3.8 mAh cm
at a current density of 0.2 mA cm
. Moreover, shallow cycling experiments (0.5 mAh cm
) boasted a capacity retention of 94% after 50 cycles, which outperformed the cycle life of prior graphene-based cathodes for this type of battery. The positive effect of the nucleotide-adsorbed nanosheets on the battery performance is discussed and related to the presence of the phosphate group in these biomolecules. Microsupercapacitors made from the interdigitated graphene patterns as the electrodes also displayed a competitive performance, affording areal and volumetric energy densities of 0.03 μWh cm
and 1.2 mWh cm
at power densities of 0.003 mW cm
and 0.1 W cm
, respectively. Taken together, by offering a green and straightforward route to different types of functional graphene-based materials, the present results are expected to ease the development of novel energy storage technologies that exploit the attractions of graphene.
A generic expression to compute triple-parton scattering (TPS) cross sections in high-energy proton–nucleus (pA) collisions is derived as a function of the corresponding single-parton cross sections ...and an effective parameter encoding the transverse parton profile of the proton. The TPS cross sections are enhanced by a factor of about
9
A
≃
2000
in pPb as compared to those in proton–nucleon collisions at the same center-of-mass energy. Estimates for triple charm (
c
c
¯
) and bottom (
b
b
¯
) production in pPb collisions at LHC and FCC energies are presented based on next-to-next-to-leading-order calculations for
c
c
¯
and
b
b
¯
single-parton cross sections. At
s
N
N
=
8.8
TeV, about 10% of the pPb events have three
c
c
¯
pairs produced in separate partonic interactions. At
s
N
N
=
63
TeV, the pPb cross sections for triple-
J
/
ψ
and triple-
b
b
¯
are
O
(1–10 mb). In the most energetic collisions of cosmic rays in the upper atmosphere, equivalent to
s
N
N
≈
400 TeV, the TPS
c
c
¯
cross section equals the total p–Air inelastic cross section.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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