Notes

Extravascular MDCT Findings involving Pulmonary Vein Stenosis in youngsters using Heart Septal Defect.
Membranes are key components in chemical purification, biological separation, and water desalination. Traditional polymeric membranes are subjected to a ubiquitous trade-off between permeance and selectivity, which significantly hinders the separation performance. Nanoporous atomically thin membranes (NATMs), such as graphene NATMs, have the potential to break this trade-off. Owing to their uniqueness of two-dimensional structure and potential nanopore structure controllability, NATMs are expected to have outstanding selectivity through molecular sieving while achieving ultimate permeance at the same time. However, a drastic selectivity discrepancy exists between the proof-of-concept demonstrations and scalable separation applications in graphene membranes. In this paper, we offer a possible solution to narrow this discrepancy by tuning the pore density and pore size separately with two successive plasma treatments. We demonstrate that by narrowing the pore size distribution, the selectivity of graphene membranes can be greatly increased. Low-energy argon plasma is first applied to nucleate high density of defects in graphene. Controlled oxygen plasma is then utilized to selectively enlarge the defects into nanopores with desired sizes. This method is scalable, and the fabricated 1 cm2 graphene NATMs with sub-nanometer pores can separate KCl and Allura Red with a selectivity of 104 and a permeance of 1.1 × 10-6 m s-1. The pores in NATMs can be further tuned from gas-selective sub-nanometer pores to a few nanometer size. The fabricated NATMs show a selectivity of 35 between CO2 and N2. With longer enlargement time, a selectivity of 21.2 between a lysozyme and bovine serum albumin can also be achieved with roughly four times higher permeance than that of a commercial dialysis membrane. This research offers a solution to realize NATMs of tunable pore size with a narrow pore size distribution for different separation processes from sub-nanometer in gas separation or desalination to a few nanometers in dialysis.Pt-based catalysts are commonly employed as NOx-trapping catalysts for automobiles, while perovskite oxides have received attention as Pt-free NOx-trapping catalysts. However, the NOx storage performance of perovskite catalysts is significantly inferior at low temperatures and with coexisting gases such as H2O, CO2, and SO2. This study demonstrates that NOx storage reactions proceed over redox site (Mn, Fe, and Co)-doped SrTiO3 perovskites. Among the examined catalysts, Mn-doped SrTiO3 exhibited the highest NOx storage capacity (NSC) and showed a high NSC even at a low temperature of 323 K. Moreover, the high NOx storage performance of Mn-doped SrTiO3 was retained in the presence of poisoning gases (H2O, CO2, and SO2). NO oxidation experiments revealed that the NSC of Co-doped SrTiO3 was dependent on the NO oxidation activity from NO to NO2 via lattice oxygen, which resulted in an inferior NSC at low temperatures. On the other hand, Mn-doped SrTiO3 successfully adsorbed NO molecules onto its surface at 323 K without the NO oxidation process using lattice oxygens. This unique adsorption behavior of Mn-doped SrTiO3 was concluded to be responsible for the high NSC in the presence of poisoning gases.Ultrahigh-temperature ceramics (UHTCs) are a group of materials with high technological interest because of their applications in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from an experimental point of view, where only few laboratories around the world have the resources to test these materials under extreme conditions, and also from a theoretical point of view, where actual methods are expensive and difficult to apply to large sets of materials. Here, a new theoretical high-throughput framework for the prediction of the thermoelastic properties of materials is introduced. This approach can be systematically applied to any kind of crystalline material, drastically reducing the computational cost of previous methodologies up to 80% approximately. This new approach combines Taylor expansion and density functional theory calculations to predict the vibrational free energy of any arbitrary strained configuration, which represents the bottleneck in other methods. Using this framework, elastic constants for UHTCs have been calculated in a wide range of temperatures with excellent agreement with experimental values, when available. Using the elastic constants as the starting point, other mechanical properties such a bulk modulus, shear modulus, or Poisson ratio have been also explored, including upper and lower limits for polycrystalline materials. Finally, this work goes beyond the isotropic mechanical properties and represents one of the most comprehensive and exhaustive studies of some of the most important UHTCs, charting their anisotropy and thermal and thermodynamical properties.Personalized wound dressings provide enhanced healing for different wound types; however multicomponent wound dressings with discretely controllable delivery of different biologically active agents are yet to be developed. Here we report 3D-printed multicomponent biocomposite hydrogel wound dressings that have been selectively loaded with small molecules, metal nanoparticles, and proteins for independently controlled release at the wound site. Hydrogel wound dressings carrying antibacterial silver nanoparticles and vascular endothelial growth factor with predetermined release profiles were utilized to study the physiological response of the wound in a mouse model. Compared to controls, the application of dressings resulted in improvement in granulation tissue formation and differential levels of vascular density, dependent on the release profile of the growth factor. Our study demonstrates the versatility of the 3D-printed hydrogel dressings that can yield varied physiological responses in vivo and can further be adapted for personalized treatment of various wound types.In the present study, three different newly developed copolymers of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with 20, 40, and 60 mol % contents in 3-hydroxyvalerate (3HV) were produced by the biotechnological process of mixed microbial cultures (MMCs) using cheese whey (CW), a by-product from the dairy industry, as feedstock. The CW-derived PHBV copolyesters were first purified and then processed by solution electrospinning, yielding fibers of approximately 2 μm in cross-section in all cases. The resultant electrospun PHBV mats were, thereafter, post-processed by annealing at different temperatures, below their maximum of melting, selected according to their 3HV content in order to obtain continuous films based on coalesced fibers, so-called biopapers. The resultant PHBV films were characterized in terms of their morphology, crystallinity, and mechanical and barrier properties to assess their potential application in food packaging. The CW-derived PHBV biopapers showed high contact transparency but3HV sample, were found to be more ductile and tougher. In terms of barrier properties, the three copolymers performed similarly to water and limonene, but to oxygen, the 40 mol % sample showed the highest relative permeability. Overall, the materials developed, which are compatible with the Circular Bioeconomy organic recycling strategy, can have an excellent potential as barrier interlayers or coatings of application interest in food packaging.Preferential oxidation (PROX) of CO in hydrogen is of great significance for proton exchange membrane fuel cells (PEMFCs) that need a CO-free hydrogen stream as fuel. The key technical problem is developing catalysts that can efficiently remove CO from the H2-rich stream within the working temperature range of PEMFCs. Herein, we design a Au/Bi2O3 interfacial catalyst for PROX with excellent catalytic performance, which can achieve 100% CO conversion in the PROX reaction over a wide temperature window (70-200 °C) and is perfectly compatible with the operating temperature window (80-180 °C) of PEMFCs. Moreover, the catalyst also demonstrates excellent high flow performance and long-term stability. Density functional theory (DFT) calculations reveal that the electrons transferring from Bi2O3 to Au and then to adsorbed perimeter CO and O2 molecules promote the activation of CO and O2, thus enhancing the catalytic performance of PROX.Nitrogen mustards are a widely used class of antitumor agents that exert their cytotoxic effects through the formation of DNA interstrand cross-links (ICLs). Despite being among the first antitumor agents used, the biological responses to NM ICLs remain only partially understood. We have previously reported the generation of NM ICL mimics by incorporation of ICL precursors into DNA using solid-phase synthesis at defined positions, followed by a double reductive amination reaction. However, the structure of these mimics deviated from the native NM ICLs. Using further development of our approach, we report a new class of NM ICL mimics that only differ from their native counterpart by substitution of dG with 7-deaza-dG at the ICL. Importantly, this approach allows for the synthesis of diverse NM ICLs, illustrated here with a mimic of the adduct formed by chlorambucil. We used the newly generated ICLs in reactions with replicative and translesion synthesis DNA polymerase to demonstrate their stability and utility for functional studies. Selleck TG003 These new NM ICLs will allow for the further characterization of the biological responses to this important class of antitumor agents.Potassium isotopic analysis is arousing increasing interest, not only in geochemistry, but also in biomedicine. However, real-life applications are still hindered by the lack of robustness of the methods used. In this work, a novel and robust method for high-precision K isotopic analysis of geological and biological samples was developed, based on the use of a multicollector ICP-mass spectrometer providing a mass resolving power of 15,000 (extra-high resolution mode, XHR). After evaluation of different measurement conditions, i.e., hot vs cold plasma conditions, standard-type vs jet-type sampling cone, and high resolution (HR) vs XHR, a combination of hot plasma conditions, use of the high-transmission jet-type sampling cone, and the XHR mode allowed for high-precision and interference-free K isotopic analysis. Potassium signal monitoring was performed in the ArH+ interference-free 0.006-0.007 amu wide peak shoulder using the XHR mode. The within-run, short-term external, and long-term external precisions for the δ41K value were 0.02‰ (2se, N = 50), 0.03‰ (2SD, N = 7), and 0.06‰ (2SD, N = 163), respectively. A two-stage chromatographic procedure was developed for the isolation of K from both geological and biological samples, and potential matrix effects affecting the K isotope ratio were systematically evaluated. The method was first applied to geological reference materials (RMs) for validation purposes, and the K isotope ratio results were in good agreement with those previously reported. Subsequently, a series of biological RMs, including serum, whole blood, cerebrospinal fluid, bovine muscle, and lobster hepatopancreas, were characterized for their K isotopic composition.
Website: https://www.selleckchem.com/products/tg003.html