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Multivariate Approaches Boosting Lithium‐Mediated Ammonia Electrosynthesis in Different Electrolytes
No full textAmmonia electrosynthesis through the lithium-mediated approach has recently reached promising results towards high activity and selectivity in aprotic media, reaching high Faradaic efficiency (FE) values and NH3 production rates. To fasten the comprehension and optimization of the complex lithium-mediated nitrogen reduction system, for the first time a multivariate approach is proposed as a powerful tool to reduce the number of experiments in comparison with the classical one-factor-at-a-time approach. Doehlert design and surface response methodology are employed to optimize the electrolyte composition for a batch autoclaved cell. The method is validated with the common LiBF4 salt, and the correlations between the FE and the amount of lithium salt and ethanol as proton donor are elucidated, also discussing their impact on the solid electrolyte interphase (SEI) layer. Moreover, a new fluorinated salt is proposed (i.e., lithium difluoro(oxalate) borate (LiFOB)), taking inspiration from lithium batteries. This salt is chosen to tailor the SEI layer, with the aim of obtaining a bifunctional interfacial layer, both stable and permeable to N2, the latter being an essential characteristic for batch systems. The SEI layer composition is confirmed strategic and its tailoring with LiFOB boosts FE values
CCEM key comparison CCEM.RF-K5c.CL
Full text linkAn international measurement comparison, identified as CCEM.RF-K5c.CL, for scattering parameters and reflection coefficients by broad-band method was conducted between twenty national metrology institutes. The purpose of the comparison is to establish the calibration measurement capability of each participating laboratory. This report presents the key comparison reference values and degree of equivalence of each participant with respect to the key comparison reference values of the comparison. The participants measured seven travelling standards, an adapter, a 20 dB attenuator, a 40 dB attenuator, two matched terminations, and two flush short terminations with 3.5 mm coaxial connectors from 0.1 GHz to 33 GHz. The pilot laboratory is National Metrology Institute of Japan (NMIJ) and the supporting laboratories are Federal Institute of Metrology (METAS) and National Physical Laboratory (NPL), National Institute of Metrology (NIM), and National Institute of Standards and Technology (NIST). Most of the reported measurement results were generally consistent, while there was a small number of outlying values
The influence of fatty acid metabolism on T cell function in lung cancer
Full text linkThe tumor microenvironment (TME) is a complex ecosystem, encompassing a variety of cellular and non-cellular elements surrounding and interacting with cancer cells, overall promoting tumor growth, immune evasion, and therapy resistance. In the context of solid tumors, factors, such as hypoxia, nutritional competition, increased stress responses, glucose demand, and PD-1 signals strongly influence metabolic alterations in the TME, highly contributing to the maintenance of a tumor-supportive and immune-suppressive milieu. Cancer cell-induced metabolic alterations partly result in an increased fatty acid (FA) metabolism within the TME, which strongly favors the recruitment of immune-suppressive M2 macrophages and myeloid-derived suppressor cells, crucial contributors to T-cell exhaustion, tumor exclusion, and decreased effector functions. The drastic pro-tumoral changes induced by the tumor metabolic rewiring result in signaling loops that support tumor progression and metastatic spreading, and negatively impact therapy efficacy. As tumor- and immune metabolism are increasingly gaining attention due to their potential therapeutic implications, we discuss the effects of altered lipid metabolism on tumor progression, immune response, and therapeutic efficacy in the context of lung cancer. In particular, we focus our analysis on the tumor-induced metabolic alterations experienced by T lymphocytes and the possible strategies to overcome immunotherapy resistance by targeting specific metabolic pathways in T cells
Lattice symmetry relaxation as a cause for anisotropic line broadening and peak shift in powder diffraction
Full text linkIn powder diffraction, lattice symmetry relaxation causes a peak to split into several components which are not resolved if the degree of desymmetrization is small (pseudosymmetry). Here the equations which rule peak splitting are elaborated for the six minimal symmetry transitions, showing that the resulting split peaks are generally broader and asymmetric, and suffer an hkl-dependent displacement with respect to the high-symmetry parent peak. These results will be of help in Rietveld refinement of pseudosymmetric structures where an exact interpretation of peak deformation is required
Experimental determination of sensitivity coefficients of some influence parameters in Rockwell B, C, 15N, 30N and 45N
Full text linkThe impact of key variables on hardness measurements, including indenter velocity, geometry, dwell times, forces, and temperature, has been extensively studied in recent decades. The recent adoption of international Rockwell hardness scale definitions has intensified this interest. While these definitions and relevant standards consider parameter ranges, the Rockwell hardness equation lacks explicit incorporation of these variables, requiring an empirical determination of their sensitivity coefficients. This study focuses on the determination of sensitivity coefficients associated with two main influential parameters − the velocity of the final load application and the time interval for the force variation from the preliminary force value to the total force value − across Rockwell B, C, 45N, 30N, and 15N hardness scales at various hardness levels, using a Monte Carlo method and multiple linear regression. The results align with findings in existing literature, enhancing the robustness and reliability of the study
Magnetostrictive nanoparticles in piezoelectric environments for spatially-confined electric brain and nerve stimulation
No full textMagnetoelectric nanomaterials are investigated in view of their application in noninvasive electrical stimulation of brain cells and nerves for the treatment of neural diseases and pain. The interplay of physical properties in nanoparticles comprised of a magnetostrictive core and a piezoelectric shell is described by modeling the core as a magnetic double-well system with uniaxial anisotropy and the shell as an array of randomly oriented piezoelectric nanocrystals. A careful analysis exploiting the symmetry of magnetic anisotropy allows to calculate the magnetostrictive deformation induced by an ac magnetic field, the resulting electric polarization and the stray electric field of the core-shell structure. An appropriate choice of the core is demonstrated to be crucial in eliciting a strong magnetoelectric response. Dispersing core-shell nanoparticles in a target tissue induces a time-dependent electric field which is always parallel to the magnetic field, permitting the directional stimulation of brain cells. Further, the properties of a magnetoelectric nanocomposite obtained dispersing bare magnetostrictive nanoparticles in a piezoelectric polymer film are investigated. It is shown that the nanocomposite submitted to an ac magnetic field generates an electric field of proper amplitude and can be used as a single flexible electrode for electrical stimulation of nerves in local analgesia
Power of a test for assessing interlaboratory consensus of nominal and ordinal characteristics of a substance, material, or object
Full text linkA concept of the consensus among different laboratories participating in an interlaboratory comparison, classifying a substance, material, or object according to its nominal and ordinal (i.e. categorical) characteristics, is devised using decomposition of the total variation of the laboratory responses. One of the components of the total variation is caused by the between-laboratory differences, and the second—by conditions associated with the applied experimental design (for example, temperature of test items, technician experience, etc). This decomposition is based on the recently developed two-way CATANOVA for nominal variables and two-way ORDANOVA for ordinal variables. The consensus is tested as hypotheses about homogeneity, i.e. insignificance of the corresponding components of the total variation. The consensus power is taken to be the power of the homogeneity test. A methodology for evaluation of the consensus power and corresponding risks of false decisions versus the dataset size of categorical characteristics obtained in an interlaboratory comparison is detailed. Examples of evaluation of the power and risks are discussed using previously-published datasets of an interlaboratory comparison of identification of weld imperfections, and an examination of the intensity of the odor of drinking water. An example of computer code in the R programming environment is presented for the power calculations in the case of nominal variables, using a chi-square distribution. A newly developed tool for ordinal variables, an Excel spreadsheet with macros, which is based on Monte Carlo draws from a multinomial distribution, is also available
Predicting Energy Loss and Permeability of Field-Annealed Amorphous and Nanocrystalline Alloys up to 1 GHz
Full text linkCrucial limitations on the permissible energy dissipation are one main factor hindering the use of soft magnetic cores at high frequencies. However, applications find limited support in present-day empirical magnetic loss models, which can hardly afford seamless high-frequency extrapolation of the predicting tools available at low frequencies. This is the case, for example, of very thin soft magnetic plates and ribbons, where the rise of eddy currents and their shielding effects at high frequencies must be attuned to the rate-dependent magnetic constitutive equation of the material. We provide in this work a comprehensive broadband (DC-1 GHz) magnetic characterization and the associated physical modeling of the energy loss and permeability properties of different types of amorphous and nanocrystalline ribbons, 6μm to 25μm thick, endowed with transverse induced anisotropy (7 - 251 J/m3) and well-defined transverse domain structure. The achieved condition of quasi-linear response and excellent broadband soft magnetic properties is shown to conform to an analytical treatment of the dynamics of the magnetization process, which is mostly accomplished by moment rotations and increasingly so under increasing frequencies. By virtue of their spatially homogeneous character, rotations provide a loss contribution matching the classical loss framework. Its broadband calculation by Maxwell's diffusion equation is carried out by introducing a rate-dependent magnetic constitutive equation of the material, worked out in terms of complex susceptibility using the Landau-Lifshitz equation. The separation between domain wall (low frequencies) and rotational (high frequencies, including spin damping and eddy currents) loss contributions is eventually obtained across a many-decade-wide frequency range