The self-assembly between graphene oxide sheets and resol-type phenolic prepolymers was investigated as a method to form three-dimensional porous carbon objects with high surface areas and low ...densities. After freeze-drying and subsequent pyrolysis of the assembled hydrogels, ultralight graphene/carbon composite aerogels with high surface areas and porosity, good conductivity, and well-defined bulk shape were obtained. By adjusting the amount of graphene oxide and resol in the precursor mixture, aerogels with a density as low as 3.2mg/cm3 or a surface area as high as 1019m2/g could be prepared. It is proposed that resol molecules are first adsorbed on the surface of graphene oxide sheets, and then the surface-coated sheets are crosslinked by the polymerization of resol prepolymers. The absorption performance was evaluated for the aerogel with the lowest density. Due to the high porosity, the aerogel displayed fast absorption rates for organic solvents as well as high absorption efficiencies. The high conductivity of the aerogels permits good performance as binderless monolithic electrodes for supercapacitors.
is a soil-dwelling unicellular eukaryote that accumulates extracellular polyphosphate (polyP). At high cell densities, when the cells are about to overgrow their food supply and starve, the ...corresponding high extracellular concentrations of polyP allow the cells to preemptively anticipate starvation, inhibit proliferation, and prime themselves to begin development. In this report, we show that starved
cells accumulate cell surface and extracellular polyP. Starvation reduces macropinocytosis, exocytosis, and phagocytosis, and we find that these effects require the G protein-coupled polyP receptor (GrlD) and two enzymes, Polyphosphate kinase 1 (Ppk1), which is required for synthesizing intracellular polyP, cell surface polyP, and some of the extracellular polyP, and Inositol hexakisphosphate kinase (I6kA), which is required for cell surface polyP and polyP binding to cells, and some of the extracellular polyP. PolyP reduces membrane fluidity, and we find that starvation reduces membrane fluidity; this effect requires GrlD and Ppk1, but not I6kA. Together, these data suggest that in starved cells, extracellular polyP decreases membrane fluidity, possibly as a protective measure. In the starved cells, sensing polyP appears to decrease energy expenditure from ingestion, and decrease exocytosis, and to both decrease energy expenditures and retain nutrients.
A non-enzymatic dopamine electrochemical sensing probe was developed. A hexagonal shape zinc-doped cobalt oxide (Zn-Co
2
O
4
) nanostructure was prepared by a facile hydrothermal approach. The ...combination of Zn, which has an abundance of electrons, and Co
3
O
4
exhibited a synergistically electron-rich nanocomposite. The crystallinity of the nanostructure was investigated using X-ray diffraction. A scanning electron microscope (SEM) was used to examine the surface morphology, revealing hexagonal nanoparticles with an average particle size of 400 nm. High-resolution transmission electron microscopy (HR-TEM) was used to confirm the nanostructure of the doped material. The nanostructure’s bonding and functional groups were verified using Fourier transform infrared spectroscopy (FTIR). The electrochemical characterization was conducted by using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and amperometry. The resistivity of the electrode was confirmed through EIS and showed that the bare glassy carbon electrode (GCE) exhibited higher charge transfer resistance as compared to modified Zn-Co
2
O
4
/GCE. The sensing probe was developed by modifying the surface of GCE with Zn-Co
2
O
4
nanostructure and tested as an electrochemical sensor for dopamine oxidation; it operated best at a working potential of 0.17 V (vs Ag/AgCl). The developed sensor exhibited a low limit of detection (0.002 µM), a high sensitivity (126 µA. µM
−1
cm
−2
), and a wide linear range (0.2 to 185 µM). The sensor showed a short response time of < 1 s. The sensor’s selectivity was investigated in the presence of coexisting species (uric acid, ascorbic acid, adrenaline, epinephrine, norepinephrine, histamine, serotonin, tyramine, phenethylamine, and glucose) with no effects on dopamine determination results. The developed sensor was also successfully used for determining dopamine concentrations in a real sample.
Graphical abstract
Aims: Compelling evidence encourages the use of the radial artery (RA) as the second arterial graft in coronary artery bypass grafting (CABG). However, its long-term benefits remain disputed. We ...sought to evaluate long-term outcome and survival by comparing patients receiving RAs with those receiving venous grafts to a single internal thoracic artery (ITA).Methods: We analyzed 345 patients undergoing primary multivessel CABG and conducted a 13-year long follow-up. In all, 187 patients received the RA and the left ITA as T-graft; 158 patients received saphenous veins complementing a single ITA. We performed propensity-score matching on 81 pairs to balance treatment selection and confounders.Results: Patients receiving RAs were younger and less likely to be female or to have pulmonary hypertension, impaired renal function, or left main coronary disease.At 30 days, they showed significantly lower unadjusted mortality and renal impairment. Unadjusted long-term survival was superior in the RA group, even after propensity-score matching. We found that RA use protected from late mortality.Conclusions: Using the RA and the left ITA as T-graft is associated with a significant long-term survival benefit in patients undergoing CABG. It may display a promising alternative to conventional use of a single ITA supplemented by saphenous veins.
Stable suspensions of zeolite nanosheets (3 nm thick MFI layers) were prepared in ethanol following acid treatment, which partially removed the associated organic structure‐directing agent. ...Nanosheets from these suspensions could then be dispersed at the air–water interface and transferred to silicon wafers using Langmuir–Schaefer deposition. Using layer‐by‐layer deposition, control on coating thickness was demonstrated. In‐plane X‐ray diffraction (XRD) revealed that the deposited nanosheets contract upon calcination similar to bulk MFI crystals. Different methods for secondary growth resulted in preferentially oriented thin films of MFI, which had sub‐12‐nm thickness in certain cases. Upon calcination, there was no contraction detectable by in‐plane XRD, indicating well‐intergrown MFI films that are strongly attached to the substrate.
Zeolite films: Acid treatment was used to prepare stable suspensions of MFI zeolite nanosheets in ethanol. Nanosheets from these suspensions showed high surface activity and could be transferred using the Langmuir–Schaefer technique to obtain monolayer coatings (3 nm thick). Secondary growth of the monolayer coatings resulted in sub‐12 nm intergrown zeolite thin films.
Although most bacteria are quickly killed after phagocytosis by a eukaryotic cell, some pathogenic bacteria escape death after phagocytosis. Pathogenic
species secrete polyP, and the polyP is ...necessary for the bacteria to prevent their killing after phagocytosis. Conversely, exogenous polyP prevents the killing of ingested bacteria that are normally killed after phagocytosis by human macrophages and the eukaryotic microbe
. This suggests the possibility that in these cells, a signal transduction pathway is used to sense polyP and prevent killing of ingested bacteria. In this report, we identify key components of the polyP signal transduction pathway in
. In cells lacking these components, polyP is unable to inhibit killing of ingested bacteria. The pathway components have orthologs in human cells, and an exciting possibility is that pharmacologically blocking this pathway in human macrophages would cause them to kill ingested pathogens such as
.
OBJECTIVES
Choice of prosthesis type in middle-aged patients undergoing aortic valve replacement (AVR) is still debated. The aim of this study is to compare long-term follow-up results in middle-aged ...patients who underwent isolated AVR with a biological or mechanical prosthesis.
METHODS
A retrospective analysis of a single-centre database was performed to identify patients aged between 55 and 65 years old who underwent isolated AVR with a biological or mechanical prosthesis from January 1996 to January 2008. Sixty patients with a biological aortic valve prosthesis (Group A) were identified and matched through propensity score analysis to other 60 patients with a mechanical aortic valve prosthesis (Group B).
RESULTS
There was no difference among groups regarding postoperative complications. Follow-up amounted to 117 ± 51 months. In Group A and B patients, 10- and 15-year survival was 77 ± 6 vs 75 ± 6 and 54 ± 13 vs 53 ± 8%, respectively (P = 0.95); 10- and 15-year freedom from structural valve deterioration, 81 ± 7 vs 100 and 64 ± 12 vs 93 ± 5%, respectively (P = 0.003); 10- and 15-year freedom from redo AVR, 87 ± 6 vs 91 ± 5 and 73 ± 11 vs 91 ± 5%, respectively (P = 0.04); 10- and 15-year freedom from endocarditis, 94 ± 3 vs 98 ± 2 and 83 ± 8 vs 98 ± 2%, respectively (P = 0.05); 10- and 15-year freedom from bleeding events, 98 ± 2 vs 96 ± 5 and 88 ± 6 vs 77 ± 10%, respectively (P = 0.98); and 10- and 15-year freedom from cerebrovascular events, 94 ± 3 vs 97 ± 3 and 83 ± 8 vs 97 ± 3%, respectively (P = 0.03).
CONCLUSIONS
While survival was not different among groups, patients with a biological prosthesis showed a higher valve-related morbidity at follow-up. Therefore, middle-aged patients should preferably receive a mechanical prosthesis.
The management of an incidental patent foramen ovale found during planned cardiac surgery remains a challenge, and current guidelines are not helpful. Although evidence is accumulating, that closure ...of an incidental found patent foramen ovale might be beneficial, especially in planned off-pump procedures, the diagnosis of a formerly unknown patent foramen ovale with the patient on the operation table has vast consequences by making it necessary to switch to on pump, bi-caval cannulation for patent foramen ovale closure. We therefore developed a technique for transatrial closure of a patent foramen ovale, guided by transesophageal echocardiography.
We have performed this surgery in 9 patients. None of them had a previously diagnosed patent foramen ovale. Mean age was 74 (±5) years, Operation time was 175 min (± 34 min), Clamp time 35 min (± 16 min) and Cardiopulmonary bypass time 80 (±17 min). Mortality was 0%. Periprocedural transesophageal echocardiography revealed closure of the patent foramen ovale in all cases.
We report a new surgical method for transoesophageal echocardiography controlled closure of a patent foramen ovale without the need for an atriotomy. This new technique is especially useful for the closure of patent foramen ovale in the setting of on-pump and off-pump coronary artery bypass graft surgeries alike.
This work focuses on the preparation of aerogel composite beads based on Zn(II)-crosslinked alginate and loaded with different percentages of AgNPs using a simple approach. The obtained samples were ...evaluated in two different applications: the first application consists in their use as catalysts for the reduction of MB, MO, OG and CR dyes in a simple and binary system under the presence of NaBH
. For this, several parameters affecting the catalytic behavior of these catalysts have been investigated and discussed such as the catalyst mass, AgNPs content, dye nature, and the selectivity of the catalyst in a binary system. The second application concerns their antibacterial activities towards two Gram-negative bacteria
(ATCC 25922), and
(ATCC 27853), and a Gram-positive bacteria
(ATCC 25923). The physico-chemical properties of different samples were characterized by XRD, FTIR, SEM/EDS, and TGA analysis. The obtained results confirmed the presence of AgNPs on a highly porous alginate structure. The dispersion of a high percentage of AgNPs leads to the formation of nanoparticles on the outer surface of the alginate which led to their leaching after the catalytic test, while the composite having a low percentage of AgNPs showed good results through all dyes without leaching of AgNPs. For the antibacterial application of the different samples, it was shown that a composite with a higher percentage of AgNPs was the most effective against all bacteria.
Two trimellitic anhydride-functionalized, thermally reduced graphenes with different aspect ratios, A f, and the same C/O ratio (8:1) were prepared and melt-mixed into poly(ethylene terephthalate) ...(PET), and the mechanical properties of the resulting nanocomposites were studied with a focus on plastic deformation behavior. A slight increase in the G′ of the melt was observed for the surface-modified low-A f graphene composites (A f = 20) below the percolation threshold, whereas a significant enhancement in G′ was observed for higher-A f graphene composites (A f = 80) at all graphene loadings, both below and above the percolation concentration. Furthermore, the use of modified low-A f graphene caused an improvement both in Young’s modulus and elongation at break of the resulting PET nanocomposites because of enhancement of interfacial adhesion between filler and matrix which resulted in the formation of a coupled network via covalent bonding and the suppression both of strain-induced orientation and strain-induced crystallization. By contrast, the use of modified higher-A f surface graphene in nanocomposites caused a drastic improvement in Young’s modulus but lower elongation-at-break than with the unmodified counterpart; the former effect is due to the formation of denser coupled networks and stronger interfacial adhesion as a result of graphene surface modification and the latter is due to the added geometrical restriction in unentangling chains from the PET matrix in the presence of higher-A f graphene. The preceding observations demonstrate the potential impacts of tuning both surface chemistry and aspect ratio of graphene in the fabrication of PET/graphene composites.
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