Abstract: Nanoscale TiO2 photocatalysts are widely used for biomedical applications, self-cleaning processes and wastewater treatments. The impregnation/deposition of TiO2 nanoparticles is indispensable for facile handling and separation as well as the improvement of their photocatalytic performance. In the present study, ordered mesoporous COK-12 silica thin platelets with a high-aspect-ratio and rough surfaces are demonstrated as a potential nanoporous support for homogeneous TiO2 nanoparticle coatings with high loading up to 16.7 wt%. The photocatalytic composite of COK-12 platelets and TiO2 nanoparticles is characterized in detail by HRSEM, SAXS, XRD, N2 physisorption analysis, solid-state UV-vis spectroscopy, HAADF-STEM, EDX analysis, and electron tomography. HAADF-STEM-EDX and electron tomography studies reveal a homogeneous dispersion of nanosized TiO2 nanoparticles over COK-12 platelets. The final composite material with anatase TiO2 nanoparticles that demonstrate a blueshifted semiconductor band gap energy of 3.2 eV coated on a highly porous COK-12 support shows exceptional photocatalytic catalytic activity for photodegradation of organic dyes (rhodamine 6G and methylene blue) and an organic pollutant (1-adamantanol) under UV light radiation, outperforming the commercial P25 TiO2 (Degussa) catalyst.

Abstract: An attempt to grow a thin epitaxial composite film of YBa2Cu3O7−δ (YBCO) with spinel MnFe2O4 (MFO) nanoparticles on a LAO substrate using the CSD approach resulted in a decomposition of the spinel and various doping modes of YBCO with the Fe and Mn cations. These nanostructural effects lead to a lowering of T c and a slight J c increase in field. Using a combination of advanced transmission electron microscopy (TEM) techniques such as atomic resolution high-angle annular dark field scanning TEM, energy dispersive x-ray spectroscopy and electron energy-loss spectroscopy we have been able to decipher and characterize the effects of the Fe and Mn doping on the film architecture. The YBaCuFeO5 anion-deficient double perovskite phase was detected in the form of 3D inclusions as well as epitaxially grown lamellas within the YBCO matrix. These nano-inclusions play a positive role as pinning centers responsible for the J c/J sf (H) dependency smoothening at high magnetic fields in the YBCO-MFO films with respect to the pristine YBCO films.

Abstract: Plasma-enhanced chemical deposition (PECVD) of carbon nanotubes has already been shown to allow chirality control to some extent. In PECVD, however, etching may occur simultaneously with the growth, and the occurrence of intermediate processes further significantly complicates the growth process.
We here employ a computational approach with experimental support to study the plasma-based formation of Ni nanoclusters, Ni-catalyzed CNT growth and subsequent etching processes, in order to understand the underpinning nanoscale mechanisms. We find that hydrogen is the dominant factor in both the re-structuring of a Ni film and the subsequent appearance of Ni nanoclusters, as well as in the CNT nucleation and etching processes. The obtained results are compared with available theoretical and experimental studies and provide a deeper understanding of the occurring nanoscale mechanisms in plasma-assisted CNT nucleation and growth.

Abstract: <script type='text/javascript'>document.write(unpmarked('We show the possibility to tune the pore size of mesoporous TiO2 templated by non-ionic block copolymers by adding different inorganic acids at well-chosen concentration. The effect of the inorganic anions on both the TiO2 cluster formation and the non-ionic block copolymers micelles is investigated to explain the experimental results.'));

Abstract: Plasma technology is gaining increasing interest for CO2 conversion, but to maximize the energy efficiency, it is important to track the different energy transfers taking place in the plasma. In this paper, we study these mechanisms by a 0D chemical kinetics model, including the vibrational kinetics, for different conditions of reduced electric field, gas temperature and ionization degree, at a pressure of 100 mbar. Our model predicts a maximum conversion and energy efficiency of 32% and 47%, respectively, at conditions that are particularly beneficial for energy efficient CO2 conversion, i.e. a low reduced electric field (10 Td) and a low gas temperature (300 K). We study the effect of the efficiency by which the vibrational energy is used to dissociate CO2, as well as of the activation energy of the reaction CO2+O→CO+O2, to elucidate the theoretical limitations to the energy
efficiency. Our model reveals that these parameters are mainly responsible for the limitations in the energy efficiency. By varying these parameters, we can reach a maximum conversion and energy efficiency of 86%. Finally, we derive an empirical formula to estimate the maximum possible energy efficiency that can be reached under the assumptions of the model.

Abstract: In recent years, the interest in treating cancer cells with plasma treated media (PTM) and plasma treated water (PTW) has increased tremendously. However, the actions of PTM and PTW are still not entirely understood. For instance, it is not clear whether the action of PTM is due to a modification in proteins/amino acids after plasma treatment of the media, or due to reactive oxygen and nitrogen species (RONS) generated from the plasma, or a combination of both effects. To differentiate between the actions of RONS and modified proteins/amino acids on the treatment of cancer cells, we compared the effects of PTM and PTW on two different pancreatic ductal adenocarcinomas (MiaPaca-2, BxPc3) and pancreatic stellate cells
(PSCs) (hPSC128-SV). PSCs closely interact with cancer cells to create a tumor-promoting environment that stimulates local tumor progression and metastasis. We treated culture media and deionized water with a cold atmospheric plasma (CAP) jet, and subsequently applied this PTM/PTW at various ratios to the pancreatic cancer and PSC cell lines. We evaluated cell death, intracellular ROS concentrations and the mRNA expression profiles of four oxidative stress-related genes, i.e. Mitogen-activated protein kinase 7 (MAPK7), B-cell lymphoma 2 (BCL2), Checkpoint kinase 1 (CHEK1) and DNA damage-inducible transcript 3, also known as C/EBP homologous protein (CHOP). Our findings demonstrate that PTM and PTW have a similar efficacy to kill pancreatic cancer cells, while PTW is slightly more effective in killing PSCs, as compared to PTM. Furthermore, we observed an enhancement of the intracellular ROS concentrations in both pancreatic cancer cells and PSCs. Thus, it is likely that under our experimental conditions, the anti-cancer activity of PTM can be attributed more to the RONS present in the treated liquid, than to the modification of proteins/amino acids in the media. Furthermore, the fact that the chemo-resistant PSCs were killed by PTM/PTW may offer possibilities for new anti-cancer therapies for pancreatic cancer cells, including PSCs.

Abstract: Single atom detection is of key importance to solving a wide range of scientific and technological problems. The strong interaction of electrons with matter makes transmission electron microscopy one of the most promising techniques. In particular, aberration correction using scanning transmission electron microscopy has made a significant step forward toward detecting single atoms. However, to overcome radiation damage, related to the use of high-energy electrons, the incoming electron dose should be kept low enough. This results in images exhibiting a low signal-to-noise ratio and extremely weak contrast, especially for light-element nanomaterials. To overcome this problem, a combination of physics-based model fitting and the use of a model-order selection method is proposed, enabling one to detect single atoms with high reliability.

Abstract: The presence of iodide ions during the growth of gold nanorods strongly affects the shape of the final products, which is proposed to be due to selective iodide adsorption on certain crystallographic facets. Therefore, a detailed structural and morphological characterization of the starting rods is crucial toward understanding this effect. Electron tomography is used to determine the crystallographic indices of the lateral facets of gold nanorods, as well as those present at the tips. Based on this information, density functional theory calculations are used to determine the surface and interface energies of the observed facets and provide insight into the relationship between the amount of iodide ions in the growth solution and the final morphology of anisotropic gold nanoparticles.

Abstract: Solar energy plays an important role in solving serious environmental
problems and meeting the high energy demand. However, the lack of suitable
materials hinders further progress of this technology. Here, we present the largest
inorganic solar cell material search till date using density functional theory (DFT) and
machine-learning approaches. We calculated the spectroscopic limited maximum
efficiency (SLME) using the Tran−Blaha-modified Becke−Johnson potential for 5097
nonmetallic materials and identified 1997 candidates with an SLME higher than 10%,
including 934 candidates with a suitable convex-hull stability and an effective carrier
mass. Screening for two-dimensional-layered cases, we found 58 potential materials
and performed G0W0 calculations on a subset to estimate the prediction uncertainty. As the above DFT methods are still computationally expensive, we developed a high accuracy machine-learning model to prescreen efficient materials and applied it to over a million materials. Our results provide a general framework and universal strategy for the design of high-efficiency solar
cell materials. The data and tools are publicly distributed at: https://www.ctcms.nist.gov/~knc6/JVASP.html, https://www.
ctcms.nist.gov/jarvisml/, https://jarvis.nist.gov/, and https://github.com/usnistgov/jarvis.

Abstract: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with a low response to treatment and a five-year survival rate below 5%. The ineffectiveness of treatment is partly because of an immunosuppressive tumor microenvironment, which comprises tumor-supportive pancreatic stellate cells (PSCs). Therefore, new therapeutic strategies are needed to tackle both the immunosuppressive PSC and pancreatic cancer cells (PCCs). Recently, physical cold atmospheric plasma consisting of reactive oxygen and nitrogen species has emerged as a novel treatment option for cancer. In this study, we investigated the cytotoxicity of plasma-treated phosphate-buffered saline (pPBS) using three PSC lines and four PCC lines and examined the immunogenicity of the induced cell death. We observed a decrease in the viability of PSC and PCC after pPBS treatment, with a higher efficacy in the latter. Two PCC lines expressed and released damage-associated molecular patterns characteristic of the induction of immunogenic cell death (ICD). In addition, pPBS-treated PCC were highly phagocytosed by dendritic cells (DCs), resulting in the maturation of DC. This indicates the high potential of pPBS to trigger ICD. In contrast, pPBS induced no ICD in PSC. In general, pPBS treatment of PCCs and PSCs created a more immunostimulatory secretion profile (higher TNF-α and IFN-γ, lower TGF-β) in coculture with DC. Altogether, these data show that plasma treatment via pPBS has the potential to induce ICD in PCCs and to reduce the immunosuppressive tumor microenvironment created by PSCs. Therefore, these data provide a strong experimental basis for further in vivo validation, which might potentially open the way for more successful combination strategies with immunotherapy for PDAC.

Abstract: Organic and biological compounds (especially those related to the pharmaceutical industry) have always been of great interest for researchers due to their importance for the development of new drugs to diagnose, cure, treat or prevent disease. As many new API (active pharmaceutical ingredients) and their polymorphs are in nanocrystalline or in amorphous form blended with amorphous polymeric matrix (known as amorphous solid dispersion—ASD), their structural identification and characterization at nm scale with conventional X-Ray/Raman/IR techniques becomes difficult. During any API synthesis/production or in the formulated drug product, impurities must be identified and characterized. Electron energy loss spectroscopy (EELS) at high energy resolution by transmission electron microscope (TEM) is expected to be a promising technique to screen and identify the different (organic) compounds used in a typical pharmaceutical or biological system and to detect any impurities present, if any, during the synthesis or formulation process. In this work, we propose the use of monochromated TEM-EELS, to analyze selected peptides and organic compounds and their polymorphs. In order to validate EELS for fingerprinting (in low loss/optical region) and by further correlation with advanced DFT, simulations were utilized.

Abstract: The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) A, b = 12.493(3) A, c = 3.95333(15) A. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations.

Abstract: The structural complexity of the antiferromagnetic oxide selenide CaFeSeO is described. The compound contains puckered FeSeO layers composed of FeSe2O2 tetrahedra sharing all their vertexes. Two polymorphs coexist that can be derived from an archetype BaZnSO structure by cooperative tilting of the FeSe2O2 tetrahedra. The polymorphs differ in the relative arrangement of the puckered layers of vertex-linked FeSe2O2 tetrahedra. In a noncentrosymmetric Cmc21 polymorph (a = 3.89684(2) A, b = 13.22054(8) A, c = 5.93625(2) A) the layers are related by the C-centering translation, while in a centrosymmetric Pmcn polymorph, with a similar cell metric (a = 3.89557(6) A, b = 13.2237(6) A, c = 5.9363(3) A), the layers are related by inversion. The compound shows long-range antiferromagnetic order below a Neel temperature of 159(1) K with both polymorphs showing antiferromagnetic coupling via Fe-O-Fe linkages and ferromagnetic coupling via Fe-Se-Fe linkages within the FeSeO layers. The magnetic susceptibility also shows evidence for weak ferromagnetism which is modeled in the refinements of the magnetic structure as arising from an uncompensated spin canting in the noncentrosymmetric polymorph. There is also a spin glass component to the magnetism which likely arises from the disordered regions of the structure evident in the transmission electron microscopy.