Abstract
Electrochemical reduction of carbon dioxide is a clean and highly attractive strategy for the production of organic products. However, this is hindered severely by the high negative ...potential required to activate carbon dioxide. Here, we report the preparation of a copper-electrode onto which the porous metal–organic framework Cu
2
(L) H
4
L = 4,4′,4″,4′′′-(1,4-phenylenebis(pyridine-4,2,6-triyl))tetrabenzoic acid can be deposited by electro-synthesis templated by an ionic liquid. This decorated electrode shows a remarkable onset potential for reduction of carbon dioxide to formic acid at −1.45 V vs. Ag/Ag
+
, representing a low value for electro-reduction of carbon dioxide in an organic electrolyte. A current density of 65.8 mA·cm
−2
at −1.8 V vs. Ag/Ag
+
is observed with a Faradaic efficiency to formic acid of 90.5%. Electron paramagnetic resonance spectroscopy confirms that the templated electro-synthesis affords structural defects in the metal–organic framework film comprising uncoupled Cu(II) centres homogenously distributed throughout. These active sites promote catalytic performance as confirmed by computational modelling.
Radial artery cannulation is extremely challenging in neonatal patients. Herein, we compared the success rate of the modified dynamic needle tip positioning short-axis, out-of-plane, ...ultrasound-guided technique with that of the traditional palpation technique in neonatal radial artery cannulation.
Sixty term neonates undergoing major abdominal surgery were randomized into the ultrasound or palpation group via the sealed-envelope method. The ultrasound group underwent radial artery cannulation using an ultrasonic apparatus, while traditional palpation of arterial pulsation was used in the palpation group. The arterial diameter and depth were measured on ultrasound before the puncture. We recorded age, weight, sex, and other background characteristics. The primary outcomes included the first-attempt, total success rates, and the total puncture procedure duration. Secondary outcomes included the incidence of complications (hematoma and thrombosis). Data were compared between the 2 groups.
Sixty term neonates were enrolled in the study. The success rates of the first attempt in the ultrasound and palpation groups were 40% (n = 30) and 10% (n = 30), respectively (P = .007; relative risk, 4.0; 95% confidence interval, 1.3-12.8). The total success rate was 96.7% in the ultrasound group and 60.0% in the palpation group (P = .001; relative risk, 1.61; 95% confidence interval, 1.19-2.17). The average time to accomplish radial artery cannulation in the ultrasound and palpation groups was 91.4 ± 55.4 and 284.7 ± 153.6 seconds, respectively (P < .001; estimated difference, -193; 95% confidence interval, -256 to -130). In addition, 3.3% of the patients in the ultrasound group and 26.7% in the palpation group suffered puncture hematoma (P = .026; relative risk, 0.13; 95% confidence interval, 0.02-0.94).
Modified dynamic needle tip positioning short-axis, out-of-plane, ultrasound-guided radial artery cannulation in neonates improves the first-attempt and total success rates and decreases the total procedural time and incidence of cannulation-related complications.
The electrochemical synthesis of chemicals from carbon dioxide, which is an easily available and renewable carbon resource, is of great importance. However, to achieve high product selectivity for ...desirable C2 products like ethylene is a big challenge. Here we design Cu nanosheets with nanoscaled defects (2–14 nm) for the electrochemical production of ethylene from carbon dioxide. A high ethylene Faradaic efficiency of 83.2% is achieved. It is proved that the nanoscaled defects can enrich the reaction intermediates and hydroxyl ions on the electrocatalyst, thus promoting C–C coupling for ethylene formation.
Developing highly efficient electrocatalysts based on cheap and earth-abundant metals for CO
reduction is of great importance. Here we demonstrate that the electrocatalytic activity of ...manganese-based heterogeneous catalyst can be significantly improved through halogen and nitrogen dual-coordination to modulate the electronic structure of manganese atom. Such an electrocatalyst for CO
reduction exhibits a maximum CO faradaic efficiency of 97% and high current density of ~10 mA cm
at a low overpotential of 0.49 V. Moreover, the turnover frequency can reach 38347 h
at overpotential of 0.49 V, which is the highest among the reported heterogeneous electrocatalysts for CO
reduction. In situ X-ray absorption experiment and density-functional theory calculation reveal the modified electronic structure of the active manganese site, on which the free energy barrier for intermediate formation is greatly reduced, thus resulting in a great improvement of CO
reduction performance.
The use of aluminum for plasmonic nanostructures opens up new possibilities, such as access to short-wavelength regions of the spectrum, complementary metal–oxide–semiconductor (CMOS) compatibility, ...and the possibility of low-cost, sustainable, mass-producible plasmonic materials. Here we examine the properties of individual Al nanorod antennas with cathodoluminescence (CL). This approach allows us to image the local density of optical states (LDOS) of Al nanorod antennas with a spatial resolution less than 20 nm and to identify the radiative modes of these nanostructures across the visible and into the UV spectral range. The results, which agree well with finite difference time domain (FDTD) simulations, lay the groundwork for precise Al plasmonic nanostructure design for a variety of applications.
To develop photocatalysts with desirable compositions and structures for improving the efficiency and selectivity of CO2 conversion to CH4 under mild conditions is of great importance. Here, we ...design an effective photocatalyst of bimetal (Ag/Pd) nanoalloys supported on nitrogen-doped TiO2 nanosheet for CO2 conversion. Such a novel photocatalyst combines multiple advantages of abundant Ti3+ ions, oxygen vacancies, and substitutional nitrogen that are favorable for catalyzing CO2 reduction. It was found that CO2 could be efficiently transformed to CH4 under mild conditions, i.e., in aqueous solution and at atmospheric pressure and room temperature. The maximum production rate of CH4 can reach 79.0 μmol g–1 h–1. Moreover, the Ag/Pd bimetals supported on N-doped TiO2 nanosheet exhibit high selectivity to CH4. The as-synthesized photocatalyst can be well recycled for CO2 reduction.
Vivid, full-color aluminum plasmonic pixels Olson, Jana; Manjavacas, Alejandro; Liu, Lifei ...
Proceedings of the National Academy of Sciences - PNAS,
10/2014, Letnik:
111, Številka:
40
Journal Article
Recenzirano
Odprti dostop
Aluminum is abundant, low in cost, compatible with complementary metal-oxide semiconductor manufacturing methods, and capable of supporting tunable plasmon resonance structures that span the entire ...visible spectrum. However, the use of Al for color displays has been limited by its intrinsically broad spectral features. Here we show that vivid, highly polarized, and broadly tunable color pixels can be produced from periodic patterns of oriented Al nanorods. Whereas the nanorod longitudinal plasmon resonance is largely responsible for pixel color, far-field diffractive coupling is used to narrow the plasmon linewidth, enabling monochromatic coloration and significantly enhancing the far-field scattering intensity of the individual nanorod elements. The bright coloration can be observed with p-polarized white light excitation, consistent with the use of this approach in display devices. The resulting color pixels are constructed with a simple design, are compatible with scalable fabrication methods, and provide contrast ratios exceeding 100:1.
Significance Full-color displays are typically fabricated using a combination of chromatic materials of various types, introduced into an addressable pixel-based electronic device. Here we show that brightly colored, highly vivid pixels, directly suitable for RGB displays, can be fabricated using periodic areas of Al nanorods in each pixel. Both nanorod length and spacing are critically important in achieving strong and spectrally distinct scattering signatures across the visible spectrum. This use of a low-cost, abundant metal for achieving full-spectrum coloration is compatible with complementary metal-oxide semiconductor manufacturing methods and directly applicable to current liquid crystal display technology.
Background
Rapid central venous catheterization is critical for the rescue and perioperative management of premature infants requiring surgery. Ultrasound‐guided dynamic needle tip positioning (DNTP) ...has been widely used as a very effective technique, especially in paediatric vascular puncture and catheterization. However, for low‐weight premature newborns, central vein catheterization still poses greater difficulties for paediatricians and paediatric anaesthesiologists. This prospective randomized control study aimed to evaluate the efficacy of combined short‐ and long‐axis (CSLA) internal jugular vein catheterization for premature newborns in comparison with the DNTP technique.
Methods
A total of 90 premature newborns (gestational age < 37 weeks and < 28 days after birth) who were scheduled for surgery were included in this study. All enrolled premature newborns were randomly divided into two groups (n = 45): the CSLA group and the DNTP group. We compared the first‐puncture success rate, total success rate, procedure time, number of needle passes, occurrence of complications and other outcome measures between the two groups.
Results
The two groups (n = 45 per group) were similar in sex, gestational age, weight, mean arterial blood pressure, and vein‐related measurements of the internal jugular vein. Total success was achieved in 43 (95.6%) and 36 (80.0%) patients in the CSLA and DNTP groups respectively. Compared with the DNTP group, the CSLA group showed a significantly higher first‐attempt success rate (71.1% vs 46.7%, χ2 = 5.5533, P = .0184) and significantly fewer needle passes (1.01.0‐2.0 vs 2.01.0‐3.0, χ2 = −2.6094, P = .0091). There was no significant difference between the groups in the procedure time (368304‐573 vs 478324‐79s, Z = −1.7690, P = .0769). Complications occurred in both groups, but the incidence was significantly lower in the CSLA group than in the DNTP group (6.7% vs 22.2%, χ2 = 4.4056, P = .0358).
Conclusions
Ultrasound‐guided internal jugular vein catheterization by the CSLA method is effective and safe. The CSLA method may be superior to the DNTP technique in premature newborns.
Incorporation of mesopores and active sites into metal-organic framework (MOF) materials to uncover new efficient catalysts is a highly desirable but challenging task. We report the first example of ...a mesoporous MOF obtained by templated electrosynthesis using an ionic liquid as both electrolyte and template. The mesoporous Cu(II)-MOF MFM-100 has been synthesised in 100 seconds at room temperature, and this material incorporates crystal defects with uncoupled Cu(II) centres as evidenced by confocal fluorescence microscopy and electron paramagnetic resonance spectroscopy. MFM-100 prepared in this way shows exceptional catalytic activity for the aerobic oxidation of alcohols to produce aldehydes in near quantitative yield and selectivity under mild conditions, as well as having excellent stability and reusability over repeated cycles. The catalyst-substrate binding interactions have been probed by inelastic neutron scattering. This study offers a simple strategy to create mesopores and active sites simultaneously via electrochemical formation of crystal defects to promote efficient catalysis using MOFs.
Heart failure is a common, costly, and potentially fatal condition. The cardiac sarcoplasmic reticulum Ca-ATPase (SERCA2a) plays a critical role in the regulation of cardiac function. Previously, low ...SERCA2a expression was revealed in mice with heart failure. Epigallocatechin-3-gallate (EGCG) can function as an epigenetic regulator and has been reported to enhance cardiac function. However, the underlying epigenetic regulatory mechanism is still unclear. In this study, we investigated whether EGCG can up-regulate SERCA2a via histone acetylation and play role in preventing heart failure. For this, we generated a mouse model of heart failure by performing a minimally invasive transverse aortic constriction (TAC) operation and used this to test the effects of EGCG. The TAC+EGCG group showed nearly normal cardiac function compared to that in the SHAM group. The expression of SERCA2a was decreased at both the mRNA and protein levels in the TAC group but was enhanced in the TAC+EGCG group. Levels of AcH3 and AcH3K9 were determined to decrease near the promoter region of Atp2a2 (the gene encoding SERCA-2a) in the TAC group, but were elevated in the TAC+EGCG group. Meanwhile, HDAC1 activity and binding near the Atp2a2 promoter were increased in the TAC group but decreased with EGCG addition. Further, binding levels of GATA4 and Mef2c near the Atp2a2 promoter region were reduced in TAC hearts, which might have been caused by histone hypoacetylation; this was reversed by EGCG. Together, upregulation of SERCA2a via the modification of histone acetylation plays a role in EGCG-mediated prevention of pressure overload-induced heart failure, and this might represent a novel pharmacological target for the treatment of heart failure.
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