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Spin crossover (SCO) complexes, which exhibit changes in spin state in response to external stimuli, have applications in molecular electronics and are challenging materials for computational design. We curate a dataset of 95 Fe(II) SCO complexes (SCO-95) from the Cambridge Structural Database that have available low- and high-temperature crystal structures and, in most cases, confirmed experimental spin transition temperatures (T1/2). We study these complexes using density functional theory (DFT) with 30 functionals spanning across multiple rungs of "Jacob's ladder" to understand the effect of exchange–correlation functional on electronic and Gibbs free energies associated with spin crossover. We specifically assess the effect of varying the Hartree–Fock exchange fraction (aHF) in structures and properties within the B3LYP family of functionals. We identify three best-performing functionals, a modified version of B3LYP (aHF = 0.10), M06-L, and TPSSh, that accurately predict SCO behavior for the majority of the complexes. While M06-L performs well, MN15-L, a more recently developed Minnesota functional, fails to predict SCO behavior for all complexes, which could be the result of differences in datasets used for parametrization of M06-L and MN15-L and also the increased number of parameters for MN15-L. Contrary to observations from prior studies, double-hybrids with higher aHF values are found to strongly stabilize high-spin states and therefore exhibit poor performance in predicting SCO behavior. Computationally predicted T1/2 values are consistent among the three functionals but show limited correlation to experimentally reported T1/2 values. These failures are attributed to the lack of crystal packing effects and counter-anions in the DFT calculations that would be needed to account for phenomena such as hysteresis and two-step SCO behavior. The SCO-95 set thus presents opportunities for method development, both in terms of increasing model complexity and method fidelity. [ABSTRACT FROM AUTHOR]

To accelerate the exploration of chemical space, it is necessary to identify the compounds that will provide the most additional information or value. A large-scale analysis of mononuclear octahedral transition metal complexes deposited in an experimental database confirms an under-representation of lower-symmetry complexes. From a set of around 1000 previously studied Fe(II) complexes, we show that the theoretical space of synthetically accessible complexes formed from the relatively small number of unique ligands is significantly (∼816k) larger. For the properties of these complexes, we validate the concept of ligand additivity by inferring heteroleptic properties from a stoichiometric combination of homoleptic complexes. An improved interpolation scheme that incorporates information about cis and trans isomer effects predicts the adiabatic spin-splitting energy to around 2 kcal/mol and the HOMO level to less than 0.2 eV. We demonstrate a multi-stage strategy to discover leads from the 816k Fe(II) complexes within a targeted property region. We carry out a coarse interpolation from homoleptic complexes that we refine over a subspace of ligands based on the likelihood of generating complexes with targeted properties. We validate our approach on nine new binary and ternary complexes predicted to be in a targeted zone of discovery, suggesting opportunities for efficient transition metal complex discovery. [ABSTRACT FROM AUTHOR]

Objective Internet-based patient education materials (PEMs) are often above the recommended sixth grade reading level recommended by the U.S. Department of Health and Human Services. In 2016 the U.S. Food and Drug Administration (FDA) released a warning statement against use of general anesthetic drugs in children and pregnant women due to concerns about neurotoxicity. The aim of this study is to evaluate readability, content, and quality of Internet-based PEMs on anesthesia in the pediatric population and neurotoxicity. Study Design The websites of U.S. medical centers with pediatric anesthesiology fellowship programs were searched for PEMs pertaining to pediatric anesthesia and neurotoxicity. Readability was assessed. PEM content was evaluated using matrices specific to pediatric anesthesia and neurotoxicity. PEM quality was assessed with the Patient Education Material Assessment Tool for Print. A one-sample t -test was used to compare the readability of the PEMs to the recommended sixth grade reading level. Results We identified 27 PEMs pertaining to pediatric anesthesia and eight to neurotoxicity. Mean readability of all PEMs was greater than a sixth grade reading (p <0.001). While only 13% of PEMs on anesthesia for pediatric patient mentioned the FDA warning, 100% of the neurotoxicity materials did. PEMs had good understandability (83%) and poor actionability (60%). Conclusion The readability, content, and quality of PEMs are poor and should be improved to help parents and guardians make informed decisions about their children's health care. Key Points The FDA issued a warning statement against the use of general anesthetic drugs in children and pregnant women. Readability, content, and quality of Internet-based patient education materials on the topic of neurotoxicity are poor. Improving the readability, content, and quality of PEMs could aid parents in making important health care decisions. [ABSTRACT FROM AUTHOR]

Low-cost, non-empirical corrections to semi-local density functional theory are essential for accurately modeling transition-metal chemistry. Here, we demonstrate the judiciously modified density functional theory (jmDFT) approach with non-empirical U and J parameters obtained directly from frontier orbital energetics on a series of transition-metal complexes. We curate a set of nine representative Ti(III) and V(IV) d1 transition-metal complexes and evaluate their flat-plane errors along the fractional spin and charge lines. We demonstrate that while jmDFT improves upon both DFT+U and semi-local DFT with the standard atomic orbital projectors (AOPs), it does so inefficiently. We rationalize these inefficiencies by quantifying hybridization in the relevant frontier orbitals. To overcome these limitations, we introduce a procedure for computing a molecular orbital projector (MOP) basis for use with jmDFT. We demonstrate this single set of d1 MOPs to be suitable for nearly eliminating all energetic delocalization and static correlation errors. In all cases, MOP jmDFT outperforms AOP jmDFT, and it eliminates most flat-plane errors at non-empirical values. Unlike DFT+U or hybrid functionals, jmDFT nearly eliminates energetic delocalization and static correlation errors within a non-empirical framework. [ABSTRACT FROM AUTHOR]

Rare-earth and actinide complexes are critical for a wealth of clean-energy applications. Three-dimensional (3D) structural generation and prediction for these organometallic systems remains a challenge, limiting opportunities for computational chemical discovery. Here, we introduce Architector, a high-throughput in-silico synthesis code for s-, p-, d-, and f-block mononuclear organometallic complexes capable of capturing nearly the full diversity of the known experimental chemical space. Beyond known chemical space, Architector performs in-silico design of new complexes including any chemically accessible metal-ligand combinations. Architector leverages metal-center symmetry, interatomic force fields, and tight binding methods to build many possible 3D conformers from minimal 2D inputs including metal oxidation and spin state. Over a set of more than 6,000 x-ray diffraction (XRD)-determined complexes spanning the periodic table, we demonstrate quantitative agreement between Architector-predicted and experimentally observed structures. Further, we demonstrate out-of-the box conformer generation and energetic rankings of non-minimum energy conformers produced from Architector, which are critical for exploring potential energy surfaces and training force fields. Overall, Architector represents a transformative step towards cross-periodic table computational design of metal complex chemistry. Rare-earth and actinide complexes are critical for a wealth of clean-energy applications but Three dimensional (3D) structural generation and prediction for these organometallic systems remains challenging. Here, the authors propose a high-throughput in-silico synthesis code for s-, p-, d-, and f-block mononuclear organometallic complexes. [ABSTRACT FROM AUTHOR]

We describe and experimentally demonstrate automated identification of optical modulation formats exclusively from physical-layer signal characteristics. The system identifies the data encoding as on-off keyed versus binary or quadrature phase-shift keyed, as well as auxiliary modulation profiles. The symbol clock rate and optimal dispersion compensation are also determined. We have validated this system with over 1500 test cases. These are enabling functionalities for a universal optical receiver and for a cognitive optical network architecture that optimizes utilization of available optical bandwidth. We demonstrate the capabilities of the system using a wavelength division multiplexed signal consisting of 19 channels, with multiple modulation formats and widely varying dispersions, signal strengths, and optical signal-to-noise ratios. [ABSTRACT FROM PUBLISHER]

Background/purpose Adhesive barriers secure medical devices to skin. Laboratory adhesion models are not predictive of in vivo performance. The objectives of these studies were to validate a novel peel force device, and to investigate relationships between barrier formulations, barrier width, subjective discomfort during barrier removal, and substrates. Methods Three hydrocolloid barrier formulations in three widths were adhered to ethylene/methyl acrylate film ( EMA), VITRO- SKIN® and human abdominal skin. Peel force was measured using a MTS Insight™ and a cyber DERM Inc. Mini Peel Tester ( CMPT). Subjects reported their discomfort. Results Peel forces were highly correlated between devices and highly dependent on substrate. Data suggested a weak direct association between peel force in vivo and discomfort. The 0.5″-wide barriers had the most precise peel forces measurements in vivo. A weak negative relationship between normalized peel force and barrier width on human skin was found. There was a strong positive relationship between peel force in vivo and on EMA, whereas no correlation was observed with VITRO- SKIN®. Conclusion The CMPT correlates with a standard instrument and can advantageously investigate adhesion in vivo. Barrier width and substrate impact the reliability and predictability of peel force measurements. [ABSTRACT FROM AUTHOR]

Background/aims: The ability to anticipate skin damage and subject/patient discomfort due to the removal of adhesive materials without human testing is currently limited. While standardized laboratory methods have been developed, their ability to model and predict the interaction with relevant living substrate is imperfect. The aim of this study was to assess the adhesion of various materials as a function of time using the abdomen as the body site, and determine if a relationship existed with skin damage and subject discomfort. Methods: Strips of six different materials used in medical devices and known to have different adhesive properties in the laboratory setting were tested in this study. The strips were adhered to the abdomens of normal volunteer subjects for varying periods of time. Peel force was measured under conditions developed to lessen the influence of skin elasticity. Disturbance of the skin barrier was assessed by measuring transepidermal water loss; erythema by reflectance L* a* b* measurements; skin cells removal by quantitation of dyed cells adhering to the test strips; and discomfort using subject self-assessment. Results: When measured at times from 30 min to 72 h after application, the peel force was highest for materials at 30 min. The peel force for one of the six materials, designated F, was clearly higher than the others at time points from 30 min to 48 h after application. Interestingly, this material caused less disruption to the skin barrier and was reported to cause less discomfort. Conclusions: In this system, there was not a correspondence between adhesion as measured by peel force and skin damage or self-report of discomfort. Further investigations will be required to establish the predictive value of other biophysical measurements and discomfort. [ABSTRACT FROM AUTHOR]

Dispersion compensating modules (DCM) are key components in long distance and high-speed fiber-optic transmission systems. However, many types of DCMs exhibit multipath interference (MPI) that acts as noise in transmission and degrades the bit error rate of the system. Further, MPI generated in DCMs is mostly due to forward scattering and mostly of the coherent type. This type of MPI cannot be correctly measured using conventional measurement techniques that use electrical spectrum analysis to measure post-detection noise. We demonstrate an accurate and simple method of MPI measurement using a swept wavelength system apparatus. We discuss the strengths and limitations of this measurement method and show system results of Q penalty due to MPI from concatenated DCMs. [ABSTRACT FROM AUTHOR]

Despite the great advances in synthesis and structural determination of atomically precise, thiolate-protected metal nanoclusters, our understanding of the driving forces for their colloidal stabilization is very limited. Currently there is a lack of models able to describe the thermodynamic stability of these 'magic-number' colloidal nanoclusters as a function of their atomic-level structural characteristics. Herein, we introduce the thermodynamic stability theory, derived from first principles, which is able to address stability of thiolate-protected metal nanoclusters as a function of the number of metal core atoms and thiolates on the nanocluster shell. Surprisingly, we reveal a fine energy balance between the core cohesive energy and the shell-to-core binding energy that appears to drive nanocluster stabilization. Our theory applies to both charged and neutral systems and captures a large number of experimental observations. Importantly, it opens new avenues for accelerating the discovery of stable, atomically precise, colloidal metal nanoclusters. [ABSTRACT FROM AUTHOR]