Search

Recently, we have developed a robust, basis-space implementation of the iterated stockholder atoms (BS-ISA) approach for defining atoms in a molecule. This approach has been shown to yield rapidly convergent distributed multipole expansions with a well-defined basis set limit. Here we use this method as the basis of a new approach, termed ISA-Pol, for obtaining non-local distributed frequency-dependent polarizabilities. We demonstrate how ISA-Pol can be combined with localization methods to obtain distributed dispersion models that share the many unique properties of the ISA: these models have a well-defined basis set limit, lead to very accurate dispersion energies, and, remarkably, satisfy commonly used combination rules to a good accuracy. As these models are based on the ISA, they can be expected to respond to chemical and physical changes naturally, and thus, they may serve as the basis for the next generation of polarization and dispersion models for ab initio force-field development. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we present studies of clusters assembled from polycyclic aromatic hydrocarbon (PAH) molecules similar in size to small soot particles. The clusters studied were comprised of coronene (C24H12) or pyrene (C16H10) molecules and represent the types of soot precursor molecule typically found in flame environments. A stochastic ‘basin-hopping’ global optimisation scheme was used to locate low-lying local minima on the potential energy surface of the molecular clusters. TEM-style projections of the resulting geometries show similarities with those observed experimentally in TEM images of soot particles. The mass densities of these clusters have also been calculated and are lower than bulk values of the pure crystalline PAH structures. They are also significantly lower than the standard value of 1.8g/cm3 used in our soot models. Consequently we have varied the mass density between 1.0g/cm3 and 1.8g/cm3 to examine the effects of varying soot density on our soot model and observed how the shape of the particle size distribution changes. Based on similarities between nascent soot particles and PAH clusters a more accurate soot density is likely to be significantly lower than 1.8g/cm3. As such, for modelling purposes, we recommend that the density of nascent soot should be taken to be the value obtained for our coronene cluster of 1.12g/cm3. [Copyright &y& Elsevier]

The paper collects the answers of the authors to the following questions:Is the lack of precision in the definition of many chemical concepts one of the reasons for the coexistence of many partition schemes?Does the adoption of a given partition scheme imply a set of more precise definitions of the underlying chemical concepts?How can one use the results of a partition scheme to improve the clarity of definitions of concepts?Are partition schemes subject to scientific Darwinism? If so, what is the influence of a community's sociological pressure in the "natural selection" process?To what extent does/can/should investigated systems influence the choice of a particular partition scheme?Do we need more focused chemical validation of Energy Decomposition Analysis (EDA) methodology and descriptors/terms in general?Is there any interest in developing common benchmarks and test sets for cross‐validation of methods?Is it possible to contemplate a unified partition scheme (let us call it the "standard model" of partitioning), that is proper for all applications in chemistry, in the foreseeable future or even in principle?In the end, science is about experiments and the real world. Can one, therefore, use any experiment or experimental data be used to favor one partition scheme over another? © 2019 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Pressure and temperature dependence of the negative thermal expansion in Zn(CN)2 is fully investigated using molecular dynamics simulations with a built potential model. The advantage of this study is that it allows us to reproduce the exotic behaviors of the material, including the negative thermal expansion (NTE), the reduction of NTE with elevated temperature, the pressure enhancement of NTE, and the pressure-induced softening. Results of the study provide us detailed data to link the properties in the energy space and the real space, giving us insights to understand the properties and the connections between them [ABSTRACT FROM AUTHOR]

Purpose: Lymphedema therapy is an effective tool in mitigating head and neck lymphedema morbidity and long-term fibrosis. Studies have shown the efficacy of facility-based therapy; however, access can be limited by sociodemographic factors, including socioeconomic status and transportation. This study evaluates the feasibility and effectiveness of home-based lymphedema therapy in a socially vulnerable patient population., Materials and Methods: A retrospective chart review analyzed patients who underwent home-based lymphedema exercise regimen after training with a lymphedema-trained speech language pathologist between 2019 and 2022 at a tertiary academic medical center. Patient and cancer demographics were collected. Primary outcomes measured were quality of life surveys and diet status., Results: Of the 27 patients included, 85.1 % were in the two highest quintiles of neighborhood deprivation based on national Area Deprivation Index (ADI). Treatment breakdown included 78 % who were treated with surgery, 96 % completed radiation and 59.3 % chemotherapy. Six months after initiating lymphedema therapy, most patients (59.3 %) were compliant with exercises. Quality of life scores showed trends toward improvement, but only a decrease in condition-related anxiety at 3 months (p = 0.004) reached statistical significance. Improvement in diet was significant at 6 and 9 months after initiation of treatment (p = 0.020)., Conclusions: Patient compliance rate demonstrates feasibility of home exercises for lymphedema treatment in a tertiary care setting with a socially vulnerable patient population. Home-based head and neck lymphedema treatment showed improvements in patient diet over time., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: When wounds do not respond to standard treatments, advanced therapies are recommended. One such therapy, a proprietary synthetic peptide, self-assembles into a wound matrix when applied to a wound to provide a physical-mechanical barrier that mitigates contamination, modulates inflammation, and becomes a scaffold for cell proliferation and growth. This study evaluated the safety and performance of the AC5 ® Advanced Wound System (Arch Therapeutics Inc. Framingham, Massachusetts) in the management of long-duration, non-healing, and challenging acute and chronic wounds that failed prior therapy., Materials and Methods: Fifteen participants were assigned to receive treatment with AC5 ® weekly or every other week. AC5 ® was evaluated for ease of use, and participants were evaluated for wound condition, healing progress, and local and systemic adverse reactions., Results: 64% of participants treated weekly had a >50% reduction in wound area at four weeks and 73% had a >60% reduction at eight weeks. For patients treated every other week, 25% achieved 50% wound area reduction at four weeks and 50% had a >50% reduction at eight weeks. The product was easy to apply contiguously to uneven wound geometry. There were no adverse events., Conclusion: The synthetic self-assembling peptide wound matrix was shown to be safe, effective, and simple to use in the treatment of hard-to-heal wounds. Because AC5® is easy to apply, has an unusual ability to self-assemble into a wound matrix in vivo, and affixes itself contiguously to the interstices of the tissue, AC5 ® may be particularly useful for undermined and tunneled wounds, whether acute or chronic. The results of this study imply that a once-weekly application may result in the best outcome. Further studies are suggested to confirm optimal application frequency for different wound types.

Background More research is required to understand the effects of implementing structured goal-setting on trainee engagement in competency-based clinical learning environments. Objective To explore how residents experienced a rotation-specific goal-setting intervention on geriatric medicine rotations at 2 hospitals. Methods All rotating residents were expected to complete the intervention, consisting of a SMART-based (Specific, Measurable, Achievable, Relevant, and Time-Bound) goal-setting form and feedback sessions with teaching faculty. From November 2019 to June 2021, we recruited a convenience sample of rotating residents. Study participants completed pre- and postrotation 35-item Dutch Residency Educational Climate Test (D-RECT) questionnaires to compare scores from their rotation before the geriatric rotation and a postrotation semistructured interview, which we transcribed and analyzed using principles of constant comparison and reflexive thematic analysis. Results We interviewed 12 of 58 (20.7%) residents participating in the goal-setting intervention, 11 of whom completed both D-RECT questionnaires. Participants' D-RECT scores favored the geriatric medicine rotation versus the immediately preceding clinical rotation (M=4.29±0.37; M=3.84±0.44, P =.002). Analyses of interview transcripts yielded 3 themes on how participants perceived the intervention influenced their learning experience: (1) structured forms and processes mediate, inform, and constrain goal selection; (2) interactions with faculty, patients, and system factors influenced goal enactment; and (3) unstructured assessments led to uncertainty around goal achievement. Challenges included time restrictions and unpredictable clinical opportunities. Conclusions Goal-setting appeared to help many residents direct their learning efforts and engage in collaborative processes with teaching faculty. We identified challenges limiting residents' engagement with the goal-setting intervention, which may inform the practical implementation of goal-setting in other competency-based curricula.

Competing Interests: Intérêts concurrents :: Jillian Alston déclare avoir reçu du financement des Instituts de recherche en santé du Canada. Stefan Baral a reçu des fonds du groupe Inner City Health Associates. Aaron Orkin reçoit des fonds du Département de médecine familiale et communautaire de l’Université de Toronto et de l’École de santé publique Dalla Lana indépendamment de cette étude. Sharon Straus est titulaire d’une chaire de recherche du Canada sur l’application des connaissances de niveau 1. La Fondation de la famille Slaight fournit du financement à l’initiative de sensibilisation aux refuges gériatriques et à l’évaluation du programme mentionnées dans ce texte; Jillian Alston et Sharon Straus participent à cette initiative. Aucun autre intérêt concurrent n’a été déclaré. Déclaration d’intérêts :: Sharon Straus siège au Conseil de gouvernance du JAMC et n’a pas participé au processus décisionnel éditorial de cet article.

Accurately describing long-range interactions is a significant challenge in molecular dynamics (MD) simulations of proteins. High-quality long-range potential is also an important component of the range-separated machine learning force field. This study introduces a comprehensive asymptotic parameter database encompassing atomic multipole moments, polarizabilities, and dispersion coefficients. Leveraging active learning, our database comprehensively represents protein fragments with up to 8 heavy atoms, capturing their conformational diversity with merely 78,000 data points. Additionally, the E(3) neural network (E3NN) is employed to predict the asymptotic parameters directly from the local geometry. The E3NN models demonstrate exceptional accuracy and transferability across all asymptotic parameters, achieving an R 2 of 0.999 for both protein fragments and 20 amino acid dipeptide test sets. The long-range electrostatic and dispersion energies can be obtained using the E3NN-predicted parameters, with an error of 0.07 and 0.02 kcal/mol, respectively, when compared to symmetry-adapted perturbation theory (SAPT). Therefore, our force fields demonstrate the capability to accurately describe long-range interactions in proteins, paving the way for next-generation protein force fields.

Competing Interests: Competing interests:: Jillian Alston reports funding from the Canadian Institutes of Health Research. Stefan Baral is funded by the Inner City Health Associates. Aaron Orkin is supported by the University of Toronto Department of Family and Community Medicine and the Dalla Lana School of Public Health,, outside the submitted work. Sharon Straus is funded by a Tier 1 Canada Research Chair in Knowledge Translation. The Slaight Family Foundation provides funding to the geriatric shelter outreach initiative and its program evaluation mentioned in this manuscript; Jillian Alston and Sharon Straus are involved with this initiative. No other competing interests were declared.

Modeling excited state processes in molecular crystals is relevant for several applications. A popular approach for studying excited state molecular crystals is to use cluster models embedded in point charges. In this paper, we compare the performance of several embedding models in predicting excited states and S1-S0 optical gaps for a set of crystals from the X23 molecular crystal database. The performance of atomic charges based on ground or excited states was examined for cluster models, Ewald embedding, and self-consistent approaches. We investigated the impact of various factors, such as the level of theory, basis sets, embedding models, and the level of localization of the excitation. We consider different levels of theory, including time-dependent density functional theory and Tamm-Dancoff approximation (TDA) (DFT functionals: ωB97X-D and PBE0), CC2, complete active space self-consistent field, and CASPT2. We also explore the impact of selection of the QM region, charge leakage, and level of theory for the description of different kinds of excited states. We implemented three schemes based on distance thresholds to overcome overpolarization and charge leakage in molecular crystals. Our findings are compared against experimental data, G0W0-BSE, periodic TDA, and optimally tuned screened range-separated functionals., (© 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).)

People are more likely to interact with other people of their ethnicity-a phenomenon known as ethnic homophily. In the United States, people of color are known to hold proportionately more high-contact jobs and are thus more at risk of virus infection. At the same time, these ethnic groups are on average younger than the rest of the population. This gives rise to interesting disease dynamics and non-trivial trade-offs that should be taken into consideration when developing prioritization strategies for future mass vaccine roll-outs. Here, we study the spread of COVID-19 through the US population, stratified by age, ethnicity, and occupation, using a detailed, previously-developed compartmental disease model. Based on historic data from the US mass COVID-19 vaccine roll-out that began in December 2020, we show, (i) how ethnic homophily affects the choice of optimal vaccine allocation strategy, (ii) that, notwithstanding potential ethical concerns, differentiating by ethnicity in these strategies can improve outcomes (e.g., fewer deaths), and (iii) that the most likely social context in the United States is very different from the standard assumptions made by models which do not account for ethnicity and this difference affects which allocation strategy is optimal. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics"., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Optoelectronic materials based on metal-free organic molecules represent a promising alternative to traditional inorganic devices. Significant attention has been devoted to the development of the third generation of OLEDs which are based on the temperature-activated delayed fluorescence (TADF) mechanism. In the last few years, several materials displaying ultra-long organic phosphorescence (UOP) have been designed using strategies such as crystal engineering and halogen functionalisation. Both TADF and UOP are controlled by the population of triplet states and the energy gaps between the singlet and triplet manifolds. In this paper, we explore the competition between TADF and UOP in the molecular crystals of three dichloro derivatives of 9 H -carbazol-3-yl(phenyl)methanone. We investigate the excited state mechanisms in solution and the crystalline phase and address the effects of exciton transport and temperature on the rates of direct and reverse intersystem crossing under the Marcus-Levich-Jortner model. We also analyse how the presence of isomeric impurities and the stabilisation of charge transfer states affect these processes. Our simulations explain the different mechanisms observed for the three derivatives and highlight the role of intramolecular rotation and crystal packing in determining the energy gaps. This work contributes to a better understanding of the connection between chemical and crystalline structures that will enable the design of efficient materials.

This study estimates consumers' willingness to pay for specific product (quality) and process (agronomic) attributes of table grapes, including taste, texture, external appearance, and the expected number of chemical applications, and for the breeding technology used to develop the plant. Considering varietal traits, on average our survey respondents were willing to pay the highest price premiums for specific offers of improvements in table grape taste and texture, followed by external appearance and expected number of chemical applications. Considering breeding methods, on average our respondents were willing to pay a small premium for table grapes developed using conventional breeding rather than gene editing (e.g., CRISPR). Results from a latent class model identify four different groups of consumers with distinct preferences for grape quality attributes and breeding technologies. The group of consumers most likely to reject gene editing considers both genetic engineering and gene editing to be breeding technologies that produce foods that are morally unacceptable and not safe to eat., Competing Interests: The authors have declared that no competing interest exist., (Copyright: © 2022 Uddin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Genetic and environmental manipulations, such as dietary restriction, can improve both health span and lifespan in a wide range of organisms, including humans. Changes in nutrient intake trigger often overlapping metabolic pathways that can generate distinct or even opposite outputs depending on several factors, such as when dietary restriction occurs in the lifecycle of the organism or the nature of the changes in nutrients. Due to the complexity of metabolic pathways and the diversity in outputs, the underlying mechanisms regulating diet-associated pro-longevity are not yet well understood. Adult reproductive diapause (ARD) in the model organism Caenorhabditis elegans is a dietary restriction model that is associated with lengthened lifespan and reproductive potential. To explore the metabolic pathways regulating ARD in greater depth, we performed a candidate-based genetic screen analyzing select nutrient-sensing pathways to determine their contribution to the regulation of ARD. Focusing on the three phases of ARD (initiation, maintenance, and recovery), we found that ARD initiation is regulated by fatty acid metabolism, sirtuins, AMPK, and the O-linked N-acetyl glucosamine (O-GlcNAc) pathway. Although ARD maintenance was not significantly influenced by the nutrient sensors in our screen, we found that ARD recovery was modulated by energy sensing, stress response, insulin-like signaling, and the TOR pathway. Further investigation of downstream targets of NHR-49 suggest the transcription factor influences ARD initiation through the fatty acid β-oxidation pathway. Consistent with these findings, our analysis revealed a change in levels of neutral lipids associated with ARD entry defects. Our findings identify conserved genetic pathways required for ARD entry and recovery and uncover genetic interactions that provide insight into the role of OGT and OGA., Competing Interests: The authors declare no competing interests. This article was prepared while MRB was employed at NIDDK, NIH. The opinions expressed in this article are the author’s own and do not reflect the views of the National Institute of General Medical Sciences.