Exploring Exact-Factorization-Based Trajectories for Low-Energy Dynamics near a Conical Intersection

We study low-energy dynamics generated by a two-dimensional two-state Jahn-Teller Hamiltonian in the vicinity of a conical intersection using quantum wave packet and trajectory dynamics. Recently, these dynamics were studied by comparing the adiabatic representation and the exact factorization, with the purpose to highlight the different nature of topological-phase and geometric-phase effects arising in the two theoretical representations of the same problem. Here, we employ the exact factorization to understand how to accurately model low-energy dynamics in the vicinity of a conical intersection using an approximate description of the nuclear motion that uses trajectories. We find that since nonadiabatic effects are weak but non-negligible, the trajectory-based description that invokes the classical approximation struggles to capture the correct behavior.

Vibrational Circular Dichroism Spectroscopy with a Classical Polarizable Force Field: Alanine in the Gas and Condensed Phases

Polarizable force fields are an essential component for the chemically accurate modeling of complex molecular systems with a significant degree of fluxionality, beyond harmonic or perturbative approximations. In this contribution we examine the performance of such an approach for the vibrational spectroscopy of the alanine amino acid, in the gas and condensed phases, from the Fourier transform of appropriate time correlation functions generated along molecular dynamics (MD) trajectories. While the infrared (IR) spectrum only requires the electric dipole moment, the vibrational circular dichroism (VCD) spectrum further requires knowledge of the magnetic dipole moment, for which we provide relevant expressions to be used with polarizable force fields. The AMOEBA force field was employed here to model alanine in the neutral and zwitterionic isolated forms, solvated by water or nitrogen, and as a crystal. Within this framework, comparison of the electric and magnetic dipole moments to those obtained with nuclear velocity perturbation theory based on density-functional theory for the same MD trajectories are found to agree well with one another. The statistical convergence of the IR and VCD spectra is examined and found to be more demanding in the latter case. Comparisons with experimental frequencies are also provided for the condensed phases.

The metabolic domestication syndrome of budding yeast

Cellular metabolism evolves through changes in the structure and quantitative states of metabolic networks. Here, we explore the evolutionary dynamics of metabolic states by focusing on the collection of metabolite levels, the metabolome, which captures key aspects of cellular physiology. Using a phylogenetic framework, we profiled metabolites in 27 populations of nine budding yeast species, providing a graduated view of metabolic variation across multiple evolutionary time scales. Metabolite levels evolve more rapidly and independently of changes in the metabolic network's structure, providing complementary information to enzyme repertoire. Although metabolome variation accumulates mainly gradually over time, it is profoundly affected by domestication. We found pervasive signatures of convergent evolution in the metabolomes of independently domesticated clades of Saccharomyces cerevisiae. Such recurring metabolite differences between wild and domesticated populations affect a substantial part of the metabolome, including rewiring of the TCA cycle and several amino acids that influence aroma production, likely reflecting adaptation to human niches. Overall, our work reveals previously unrecognized diversity in central metabolism and the pervasive influence of human-driven selection on metabolite levels in yeasts.

Nonadiabatic dynamics with classical trajectories: The problem of an initial coherent superposition of electronic states

Advances in coherent light sources and development of pump-probe techniques in recent decades have opened the way to study electronic motion in its natural time scale. When an ultrashort laser pulse interacts with a molecular target, a coherent superposition of electronic states is created and the triggered electron dynamics is coupled to the nuclear motion. A natural and computationally efficient choice to simulate this correlated dynamics is a trajectory-based method where the quantum-mechanical electronic evolution is coupled to a classical-like nuclear dynamics. These methods must approximate the initial correlated electron-nuclear state by associating an initial electronic wavefunction to each classical trajectory in the ensemble. Different possibilities exist that reproduce the initial populations of the exact molecular wavefunction when represented in a basis. We show that different choices yield different dynamics and explore the effect of this choice in Ehrenfest, surface hopping, and exact-factorization-based coupled-trajectory schemes in a one-dimensional two-electronic-state model system that can be solved numerically exactly. This work aims to clarify the problems that standard trajectory-based techniques might have when a coherent superposition of electronic states is created to initialize the dynamics, to discuss what properties and observables are affected by different choices of electronic initial conditions and to point out the importance of quantum-momentum-induced electronic transitions in coupled-trajectory schemes.

Investigating the Photodynamics of trans-Azobenzene with Coupled Trajectories

In this work, we present the first implementation of coupled-trajectory Tully surface hopping (CT-TSH) suitable for applications to molecular systems. We combine CT-TSH with the semiempirical floating occupation molecular orbital-configuration interaction electronic structure method to investigate the photoisomerization dynamics of trans-azobenzene. Our study shows that CT-TSH can capture correctly decoherence effects in this system, yielding consistent electronic and nuclear dynamics in agreement with (standard) decoherence-corrected TSH. Specifically, CT-TSH is derived from the exact factorization and the electronic coefficients' evolution is directly influenced by the coupling of trajectories, resulting in the improvement of internal consistency if compared to standard TSH.

Oral health-related quality of life in elderly: an umbrella review of systematic reviews from a multidisciplinary rehabilitation point-of-view

Background

Poor oral health is highly prevalent among elderlies and may impact quality of life of elderly people. In this scenario, oral health has been often linked to general health and chronic disorders, including distinct features of frailty. The aim of the present umbrella review of systematic reviews was to assess the scientific literature on the correlation between oral health related quality of life (OHRQoL) and elderly to present a multidisciplinary approach to these complex patients.

Methods

We performed a literature search of the databases Pub-Med/Medline, Scopus, Web of Science, and Physiotherapy Evidence Database electronic databases. Two independent reviewers performed the literature research from the inception to 25th November 2023 and screened the studies for eligibility.

Results

The search resulted in a total of 676 results eligible articles. After removal of duplicates and full-text screening, a total of 3 systematic reviews were considered to meet the inclusion criteria and were included for this review.

Conclusions

Frailty is very common in elderly such as a poor oral health. In this scenario, malnutrition and bad lifestyle habits may affect not only the determinism of many systemic non-communicable diseases but also oral health quality. Taken together, the findings of this umbrella review of systematic reviews showed a strict correlation between the frailty, typical condition of ageing people, and a poor OHRQoL. Therefore, it is mandatory to implement the oral health prevention with specific protocols of oral rehabilitation to improve the OHRQoL in elderly.

On the Nature of Geometric and Topological Phases in the Presence of Conical Intersections

The observable nature of topological phases related to conical intersections in molecules is studied. Topological phases should be ubiquitous in molecular processes, but their elusive character has often made them a topic of discussion. To shed some light on this issue, we simulate the dynamics governed by a Jahn-Teller Hamiltonian and analyze it employing two theoretical representations of the molecular wave function: the adiabatic and the exact factorization. We find fundamental differences between effects related to topological phases arising exclusively in the adiabatic representation, and thus not related to any physical observable, and geometric phases within the exact factorization that can be connected to an observable quantity. We stress that while the topological phase of the adiabatic representation is an intrinsic property of the Hamiltonian, the geometric phase of the exact factorization depends on the dynamics that the system undergoes and is connected to the circulation of the nuclear momentum field.

Psychopathological risk stability and change in a sample of mothers and preschool children before, during and after the peak of COVID-19 pandemic

Numerous studies have found that the COVID-19 epidemic and the measures to stop it have had a substantial impact on the mental health of the general population. Nevertheless, the majority of this research only looked at the variations in the degree of psychopathological symptoms in individuals before and after the first wave of the pandemic. In a sample of N = 380 preschoolers and their mothers assessed through the Symptom Check-List/90-R and of the Child Behaviour Check-List, the present study aimed at exploring psychopathological risk in mothers and their offspring's dysregulation levels before (T1), during (T2) and after (T3) the peak of COVID-19 pandemic. Our main results showed that mothers' relational distress increased from T1 to T2 and then increased again from T2 to T3. Moreover, maternal aggressiveness, hostility, and anxiety scores significantly decreased from T1 to T2 but slightly increased from T2 to T3. In children, dysregulation levels increased from T1 to T2 but decreased from T2 to T3. Children of mothers with clinical scores at the SCL-90/R showed significantly higher dysregulation problems at T1, T2 and T3 than children of mothers with scores below the clinical threshold. This study adds to previous literature in that it evaluates stability or change in maternal and offspring scores not only in the pre-pandemic period and during the first wave of the pandemic, but it also considers the subsequent months, focusing on a broad range of maternal symptoms, rather than assessing depressive and anxiety symptoms as most of previous research did.

Significance of Energy Conservation in Coupled-Trajectory Approaches to Nonadiabatic Dynamics

Through approximating electron-nuclear correlation terms in the exact factorization approach, trajectory-based methods have been derived and successfully applied to the dynamics of a variety of light-induced molecular processes, capturing quantum (de)coherence effects rigorously. These terms account for the coupling among the trajectories, recovering the nonlocal nature of quantum nuclear dynamics that is completely overlooked in traditional independent-trajectory algorithms. Nevertheless, some of the approximations introduced in the derivation of some of these methods do not conserve the total energy. We analyze energy conservation in the coupled-trajectory mixed quantum-classical (CTMQC) algorithm and explore the performance of a modified algorithm, CTMQC-E, where some of the terms are redefined to restore energy conservation. A set of molecular models is used as a test, namely, 2-cis-penta-2,4-dienimium cation, bis(methylene) adamantyl radical cation, butatriene cation, uracil radical cation, and neutral pyrazine.

Omics sciences and precision medicine in testicular cancer

Background

Cancer, a potentially fatal condition, is one of the leading causes of death worldwide. Among males aged 20 to 35, the most common cancer in healthy individuals is testicular cancer, accounting for 1% to 2% of all cancers in men.

Methods

Throughout this review, we have employed a targeted research approach, carefully handpicking the most representative and relevant articles on the subject. Our methodology involved a systematic review of the scientific literature to ensure a comprehensive and accurate overview of the available sources.

Results

The onset and spread of testicular cancer are significantly influenced by genetic changes, including mutations in oncogenes, tu-mor suppressor genes, and DNA repair genes. As a result of identifying these specific genetic mutations in cancers, targeted medications have been developed to disrupt the signaling pathways affected by these genetic changes. To improve the diagnosis and treatment of this disease, it is crucial to understand its natural and clinical histories.

Conclusions

In order to comprehend cancer better and to discover new biomarkers and therapeutic targets, oncologists are increasingly employing omics methods, such as genomics, transcriptomics, proteomics, and metabolomics. Targeted medications that focus on specific genetic pathways and mutations hold promise for advancing the diagnosis and management of this disease.

Effectiveness of Kinesiotaping and McConnell taping combined with physical exercise on gait biomechanics in patients with patellofemoral syndrome: non-randomized clinical trial

Background

Patellofemoral pain syndrome (PFPS) is a pathological condition of the knee, typical of young adults, characterized by diffuse pain in the anterior and / or medial part of the knee. We aimed to examine the effectiveness of the two types of taping in association with therapeutic exercise in relation to the biomechanical parameters, on pain and on functionality of the lower limb in patients with PFPS.

Methods

We collected data from patients treated in our outpatient's clinic with two kinds of bandage: the Kinesiotaping group (KG) and the McConnel taping group (MG). All subjects were evaluated trough an optoelectronic system, the Numeric Pain Rating Scale (NPRS), and with the Lower Extremity Functional Scale (LEFS) at baseline before applying the taping (T0), fifteen minutes after applying the bandage (T1), after four weeks of treatment (T2) without applying the bandage and three months after the end of the first treatment period with bandages and exercises (T3).

Results

Thirty-five patients (KG 16; MG 19) were included in the study. The most statistically significant changes over time in the LEFS and NPRS values have been recorded in the MG group compared to KG. The average speed and hip rotation showed a statistically significant increase between T3 and T0.

Conclusion

The application of the knee bandage for PFPS would appear to show improvement in NPRS and LEFS outcomes in both groups. Furthermore, in this study the MG evidenced better results and significant changes over time than KG.

First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment

We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment, which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of 5.9 ton. During the (1.09±0.03)  ton yr exposure used for this search, the intrinsic ^{85}Kr and ^{222}Rn concentrations in the liquid target are reduced to unprecedentedly low levels, giving an electronic recoil background rate of (15.8±1.3)  events/ton yr keV in the region of interest. A blind analysis of nuclear recoil events with energies between 3.3 and 60.5 keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of 2.58×10^{-47}  cm^{2} for a WIMP mass of 28  GeV/c^{2} at 90% confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

Influence of the environment on the infrared spectrum of alanine: An effective mode analysis

The vibrational spectrum of the alanine amino acid was computationally determined in the infrared range 1000-2000 cm^-1, under various environments encompassing the gas, hydrated, and crystalline phases, by means of classical molecular dynamics trajectories, carried out with the Atomic Multipole Optimized Energetics for Biomolecular Simulation polarizable force field. An effective mode analysis was performed, in which the spectra are optimally decomposed into different absorption bands arising from well-defined internal modes. In the gas phase, this analysis allows us to unravel the significant differences between the spectra obtained for the neutral and zwitterionic forms of alanine. In condensed phases, the method provides invaluable insight into the molecular origins of the vibrational bands and further shows that peaks with similar positions can be traced to rather different molecular motions.

Efficacy of ultrasound therapy combined with cryotherapy in pain management and rehabilitation in patients with Achilles tendinopathy: a retrospective observational study

Background

Achilles tendinopathy (AT) is characterized by pain, reduced performance, and swelling in and around the tendon. The aim of our study was to evaluate and compare the effects of ultrasound therapy alone or associated with cryotherapy.

Methods

We analyzed retrospectively amateur runner patients who run at least 3 times a week, with medical and ultrasound diagnosis of subacute AT of the midportion. All patients underwent 10 sessions of ultrasounds' therapy with qmd® ultrasound cryo and a therapeutic exercise with stretching and eccentric exercises. The Cryo-Ultrasound Group (CUG, 15, 8M and7/F), during the ultrasound treatment, underwent a session of cryo-ultrasound therapy. The Ultrasound Group (UD, 15, 7M and 8F) only performed ultrasound therapy.

Results

All evaluations performed show significant improvement over time in both groups. The CUG shows at T1 a greater increase in pain and function compared to the UG. Friedmann's repeated measures analysis shows that both groups improved when assessed separately over time. From the subsequent post hoc analysis, a statistically significant difference is highlighted between the values evaluated at T0 and T3.

Conclusions

The possible simultaneous delivery of the two treatment modalities, in patients suffering from tendinopathies, therefore represents a good possibility of synergistically exploiting their therapeutic actions. Future studies with a larger patient sample and longer follow-up are also needed to better evaluate the benefits of this treatment.

Gait analysis advancements: rehabilitation value and new perspectives from forensic application

The clinical and rehabilitation value of gait analysis is remarkable and indisputable and poised to grow as technological advancements unfold. This article aims to shed light on the advances in how gait is assessed, enabling those who have suffered an injury impairing their motor skills to be diagnosed more accurately and efficiently as well as to compare the hallmarks of rehabilitative and forensic gait analysis. The authors have conducted an analysis of relevant papers (published between 1967 and 2020) from a medicolegal perspective, cited in PubMed, MEDLINE, Cochrane Library, EMBASE, and available recommendations for the legal application of such techniques. Moreover, considering the use of gait analysis as a forensic tool, this study broadens the scope of research by including search engines, legal databases, and court filings (DeJure, Lexis Nexis, Justia) between 2000 and 2022. The instrumental assessment of movement (Gait Analysis) has come to constitute an essential analytical tool for the biomedical sector to objectively and accurately assess human movement and posture. The article is also aimed at elaborating differences and similarities between clinical and forensic gait analysis. When it comes to the forensic applicability of gait analysis and its evidentiary value, however, there is a pressing need for a review of its scientific basis. Therefore, it is necessary to conduct a thorough evaluation of its use in legal practice, as stressed in scientific literature and surveys. It is of utmost importance to highlight the procedural and assessment standards currently applied to forensic gait analysis, to evaluate its strengths and weaknesses, and to achieve standardized guidelines based on broad scientific consensus.

Inorganic sulfur fixation via a new homocysteine synthase allows yeast cells to cooperatively compensate for methionine auxotrophy

The assimilation, incorporation, and metabolism of sulfur is a fundamental process across all domains of life, yet how cells deal with varying sulfur availability is not well understood. We studied an unresolved conundrum of sulfur fixation in yeast, in which organosulfur auxotrophy caused by deletion of the homocysteine synthase Met17p is overcome when cells are inoculated at high cell density. In combining the use of self-establishing metabolically cooperating (SeMeCo) communities with proteomic, genetic, and biochemical approaches, we discovered an uncharacterized gene product YLL058Wp, herein named Hydrogen Sulfide Utilizing-1 (HSU1). Hsu1p acts as a homocysteine synthase and allows the cells to substitute for Met17p by reassimilating hydrosulfide ions leaked from met17Δ cells into O-acetyl-homoserine and forming homocysteine. Our results show that cells can cooperate to achieve sulfur fixation, indicating that the collective properties of microbial communities facilitate their basic metabolic capacity to overcome sulfur limitation.

The Perinatal Assessment of Paternal Affectivity (PAPA): Italian validation of a new tool for the screening of perinatal depression and affective disorders in fathers

BACKGROUND

Questionnaires for the screening of paternal perinatal psychological distress are based on clinical manifestations expressed by women, showing limitations in capturing the wide array of signs and symptoms exhibited by men. The current study aimed to validate the Perinatal Assessment of Paternal Affectivity, a new self-report tool for the screening of paternal depressive and affective disorder.

METHOD

This study used a cross-sectional design with a 3-month test-retest, involving respectively 385 (T1) and a sub-sample of 111(T2) fathers. Confirmatory factor analysis (CFA) was performed to test structural validity and concurrent validity was assessed by Spearman correlations. We assessed reliability using McDonald's ω and ordinal alpha. Group differences in PAPA scores based on sociodemographic were also tested.

RESULTS

The CFA reported a one factor structure as the optimal solution. The PAPA also showed adequate reliability and internal consistency as well as acceptable test-retest indices. Concurrent validity was confirmed by significant correlations between PAPA total score and standardized test scores. Non-Italian fathers and fathers who experienced recent stressful life events reported higher PAPA scores.

LIMITATIONS

Our sample was not homogeneous in terms of nationality and most of the participants, were from Northern Italy. Some risk factors associated with paternal parental psychological distress (e.g., unplanned pregnancy) have not been considered.

CONCLUSION

This study provides initial evidence of validity and reliability of the PAPA as a brief and sensitive screening tool to detect signs and symptoms of paternal affective disorder during both prenatal and postnatal period.

Search for New Physics in Electronic Recoil Data from XENONnT

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3)  events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Impact of Covid-19 pandemic on injection-based practice: report from an Italian multicenter and multidisciplinary survey

BACKGROUND

There are no papers exploring the impact of COVID-19 pandemic on the injection-based practice in patients affected by different rheumatic diseases, including osteoarthritis. The aim was to investigate the impact of COVID-19 pandemic on injection-based practice trough the Italian country.

STUDY DESIGN

A survey-based retrospective cross-sectional study.

METHODS

An Italian-language questionnaire was developed by a group of senior researchers and distributed by e-mail to some Rheumatology, Orthopedic and Rehabilitation Units from different geographic areas of Italy. The survey included information about the number of injections performed during COVID-19 pandemic (stratified by injected agents and injected joint), in comparison to the pre-pandemic period, and the possible reasons behind an eventual reduction. Responses were collected and descriptive analysis calculated.

RESULTS

Eleven centers of the National Health Service completed the survey. The activities of the injections services significantly decreased across the country with a percentage of reduction of 60% compared to the pre-pandemic period. A significant reduction of both intra-articular and peri-articular injections was registered. Among intra-articular. treatments, the most affected ones were the hyaluronic acid injections, when compared to corticosteroids. A significant decrease of the total amount of peri-articular injections was observed. The strict government restrictions and the fear of patients to become infected represented the most limiting factors.

CONCLUSIONS

The reported decrease of the injection-based practice in our country during the COVID-19 pandemic highlights the detrimental effects of the COVID-19 pandemic on the management of chronic musculoskeletal diseases with possible negative consequences in terms of disability and quality of life.

A post processing pipeline to prepare raw data for machine learning algorithms in cardiac magnetic resonance imaging

Funding Acknowledgements

Type of funding sources: None.

Background

Artificial Intelligence is an emergent tool in clinical practice for post processing of medical images. Machine Learning (ML) pipelines are created for data of interest extraction and algorithm application. A common issue in data extraction is represented by noisy datasets, like those of CMR studies, characterized by multiple images, acquired by different techniques, axis orientation and contrast timing.

Purpose

A ML pipeline for extraction of LGE images from raw DICOM data is presented. Additionally, steps for normalization of image number and automatically heart localization are outlined.

Methods and Results

642 consecutive CMR studies were analyzed.

Pipeline, Part 1. By looking at the metadata in raw files, ‘SequenceName’ tag was used to discard cine images, ‘ScanningSequence’ tag to select Gradient Recall and Inversion Recovery techniques (Inversion Time > 100 ms), ‘SequenceVariant’ tag to discard Steady State images (See Fig. 1). Orientation of the major axis was computed and ‘Axial’ or ‘Coronal’ images removed. Scans were grouped together by image orientation (requesting a min and max number of elements per group) and only the group with the largest number of files was selected. Finally, DICOMs were grouped by image shape (demanding a min number of elements), and only the series with the highest resolution was retained. Then, for each subject, the extracted series consists of a 3D-array (N,H,W), with N number of slices, and (H,W) image resolution. The attributes were not homogeneous between subjects.

Pipeline, Part 2. Given a desired final number of slices and resolution, the 3D-array was reshaped through a spline interpolation. In order to have a focus on the heart, a Region of Interest (ROI) extractor was implemented, based on a YOLO network for object detection. The network was applied on all the slices (Fig. 2); then the images were cropped by keeping the largest bounding box. This step allowed us to remove the background by only selecting the relevant ROIs. To manage the data more easily, images were saved as a NumPy Array, while other useful Dicom metadata (e.g. weight, age, …) were stored using the json standard.

At the end of the ML pipeline, images can be reduced to a common resolution and forwarded to ML algorithms.

By using this pipeline, a great amount of information not needed for LGE analysis can be discarded, granting a significant reduction in terms of data storage. In our series, the original dataset extended for about 200 GB; by requesting 10 slices per subject with a resolution of 128 by 128 pixels (also extracting heart ROI) the final dimension was reduced to 108 MB.

Conclusions

In this work, we presented a post-processing pipeline for CRM images and LGE analysis. Given in input raw CRM the pipeline is able to (i) remove unuseful data, (ii) extract heart ROIs storing also Dicom metadata, (iii) normalize slices and image resolution, and (iv) store the processed CRM into ready-format for ML techniques. Fig.1:Pipeline Schematic RepresentationFig.2:YOLO Heart Extraction

Myocardial fibrosis detection using kernel methods: preliminary results from a cardiac magnetic resonance study

Funding Acknowledgements

Type of funding sources: None.

Background

Asserting the presence of myocardial fibrosis from cardiac magnetic resonance (CMR) images is sometimes a complex task, even for experienced cardiac imagers. The application of artificial intelligence models to the evaluation process can be of help for enhancing diagnostic accuracy.

Purpose

In this work, we tested two different Machine Learning (ML) algorithms, namely kernel methods with Support Vector Machine (SVM) and Convolutional Neural Network (CNN) to a cohort of consecutive CMR studies. The goal was a binary classification task, aimed to identify myocardial scar (present/absent).

Methods

Dataset consisted of 642 CMR scans, equally divided into healthy and fibrosis-affected. Raw DICOM files were preprocessed through an automated pipeline, in order to retrieve only short-axis post contrast acquisitions. Heart regions were then individuated using a YOLO network, in order to remove the background and focus only on data of interest. Finally, for each subject 10 slices were extracted through interpolation, and all images resized to 128 by 128 pixels. Dataset was divided into training and test sets, with proportions 80%-20%.

Results

The first analysis was based on state-of-the-art CNN models, pre-trained on the ImageNet dataset. The training of the models was optimized using "reduce learning rate on the plateau", "early stopping", and standard data augmentation techniques. Experiments showed that CNNs-based models led to poor performances.

The second attempt was based on kernel methods and SVM. Before feeding the input to the algorithm, dimensionality reduction was implemented using a Principal Component Analysis retaining 99% of the variance. The resulting 335 features were passed as input to an SVM, testing different kernels (e.g. Linear, Gaussian, Cossim). Models were trained and optimized using a Grid Search with a 5-fold Cross-Validation. The best SVM configuration displayed an accuracy of 68% and a sensitivity of 60%.

Improved results could be obtained using state-of-the-art Multiple Kernel Learning algorithms, leading to 71% accuracy and sensitivity of 72% (with a 12% increment with respect to the previous algorithm).

Conclusions

Our preliminary results of this study showed the possibility for a ML system to learn to identify myocardial fibrosis, directly from raw CMR images. In particular, kernel methods were able to achieve good and significant results, even with small amounts of data, suggesting room for improvement. In future works, we plan to furtherly explore kernel methods to improve the results and to build an end-to-end solution for cardiac imagers.

Material radiopurity control in the XENONnT experiment

The selection of low-radioactive construction materials is of the utmost importance for rare-event searches and thus critical to the XENONnT experiment. Results of an extensive radioassay program are reported, in which material samples have been screened with gamma-ray spectroscopy, mass spectrometry, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn emanation measurements. Furthermore, the cleanliness procedures applied to remove or mitigate surface contamination of detector materials are described. Screening results, used as inputs for a XENONnT Monte Carlo simulation, predict a reduction of materials background (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼17%) with respect to its predecessor XENON1T. Through radon emanation measurements, the expected \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn activity concentration in XENONnT is determined to be 4.2 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{+0.5}_{-0.7}$$\end{document}-0.7+0.5) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}μBq/kg, a factor three lower with respect to XENON1T. This radon concentration will be further suppressed by means of the novel radon distillation system.

Exact Factorization Adventures: A Promising Approach for Non-Bound States

Modeling the dynamics of non-bound states in molecules requires an accurate description of how electronic motion affects nuclear motion and vice-versa. The exact factorization (XF) approach offers a unique perspective, in that it provides potentials that act on the nuclear subsystem or electronic subsystem, which contain the effects of the coupling to the other subsystem in an exact way. We briefly review the various applications of the XF idea in different realms, and how features of these potentials aid in the interpretation of two different laser-driven dissociation mechanisms. We present a detailed study of the different ways the coupling terms in recently-developed XF-based mixed quantum-classical approximations are evaluated, where either truly coupled trajectories, or auxiliary trajectories that mimic the coupling are used, and discuss their effect in both a surface-hopping framework as well as the rigorously-derived coupled-trajectory mixed quantum-classical approach.

Quantum dynamics with curvilinear coordinates: models and kinetic energy operator

In order to simplify the numerical solution of the time-dependent or time-independent Schrödinger equations associated with atomic and molecular motions, the use of well-adapted coordinates is essential. Usually, this set of curvilinear coordinates leads to a Hamiltonian operator that is as separable as possible. Although their corresponding kinetic energy operator (KEO) expressions can be derived analytically for small systems or special kinds of coordinates, a numerical and exact approach allows one to compute them in terms of sophisticated curvilinear coordinates. Furthermore, the numerical approach enables one to easily define reduced-dimensionality or constrained models. We present here a recent implementation of this numerical approach that allows nested coordinate transformations, therefore leading to great flexibility in the definition of the curvilinear coordinates. Furthermore, this implementation has no limitations in terms of numbers of atoms or coordinate transformations. The quantum dynamics of the cis-trans photoisomerization of part of the retinal chromophore illustrates the construction of the coordinates and KEO part of a three-dimensional model. This article is part of the theme issue 'Chemistry without the Born-Oppenheimer approximation'.

Describing the photo-isomerization of a retinal chromophore model with coupled and quantum trajectories

The exact factorization of the electron-nuclear wavefunction is applied to the study of the photo- isomerization of a retinal chromophore model. We describe such an ultrafast nonadiabatic process by analyzing the time-dependent potentials of the theory and by mimicking nuclear dynamics with quantum and coupled trajectories. The time-dependent vector and scalar potentials are the signature of the exact factorization, as they guide nuclear dynamics by encoding the complete electronic dynamics and including excited-state effects. Analysis of the potentials is, thus, essential - when possible - to predict the time-dependent behavior of the system of interest. In this work, we employ the exact time-dependent potentials, available for the numerically-exactly solvable model used here, to propagate quantum nuclear trajectories representing the isomerization reaction of the retinal chromophore. The quantum trajectories are the best possible trajectory-based description of the reaction when using the exact-factorization formalism, and thus allow us to assess the performance of the coupled-trajectory, fully approximate, schemes derived from the exact-factorization equations.

Medical management of osteoarthritis during the CO-VID-19 pandemic: a challenge for the present and the future

The ongoing Covid-19 pandemic has inevitably changed the treatment of many chronic diseases which has been suspended or has suffered dangerous slowdowns. Osteoarthritis (OA) is the most common musculoskeletal disease. As a result, the medical management of Osteoarthritis was heavily impacted by the pandemic, and it required new therapeutic strategies. The purpose of this descriptive review is to provide an overview of how much the pandemic has affected the medical management of osteoarthritis and to outline a number of possible countermeasures. The COVID-19 pandemic requires a "multimodal approach": physicians are called to test the management of Osteoarthritis patients at a distance, through the tools made available by telemedicine, for all cases in which direct contact is avoidable. Therapies that instead require a direct intervention on the patient impose that all the procedures are carried out in complete safety, scrupulously keeping to the use of personal protective equipements.

A Photochemical Reaction in Different Theoretical Representations

The Born–Oppenheimer picture has forged our representation and interpretation of photochemical processes, from photoexcitation down to the passage through a conical intersection, a funnel connecting different electronic states. In this work, we analyze a full in silico photochemical experiment, from the explicit electronic excitation by a laser pulse to the formation of photoproducts following a nonradiative decay through a conical intersection, by contrasting the picture offered by Born–Oppenheimer and that proposed by the exact factorization. The exact factorization offers an alternative understanding of photochemistry that does not rely on concepts such as electronic states, nonadiabatic couplings, and conical intersections. On the basis of nonadiabatic quantum dynamics performed for a two-state 2D model system, this work allows us to compare Born–Oppenheimer and exact factorization for (i) an explicit photoexcitation with and without the Condon approximation, (ii) the passage of a nuclear wavepacket through a conical intersection, (iii) the formation of excited stationary states in the Franck–Condon region, and (iv) the use of classical and quantum trajectories in the exact factorization picture to capture nonadiabatic processes triggered by a laser pulse.

Nonadiabatic Dynamics with Coupled Trajectories

In this paper, we discuss coupled-trajectory schemes for molecular-dynamics simulations of excited-state processes. New coupled-trajectory strategies to capture decoherence effects, revival of coherence and nonadiabatic interferences in long-time dynamics are proposed, and compared to independent-trajectory schemes. The working framework is provided by the exact factorization of the electron-nuclear wave function, and it exploits ideas emanating from various surface-hopping schemes. The new coupled-trajectory algorithms are tested on a one-dimensional two-state system using different model parameters which allow one to induce different dynamics. The benchmark is provided by the numerically exact solution of the time-dependent Schrödinger equation.

Electronic Structure and Excited States of the Collision Reaction O(3P) + C2H4: A Multiconfigurational Perspective

We present a study of the O(³P) + C₂H₄ scattering reaction, a process that takes place in the interstellar medium and is of relevance in atmospheric chemistry as well. A comprehensive investigation of the electronic properties of the system has been carried out based on multiconfigurational ab initio CASSCF/CASPT2 calculations, using a robust and consistent active space that can deliver accurate potential energy surfaces in the key regions visited by the system. The paper discloses detailed description of the primary reaction pathways and the relevant singlet and triplet excited states at the CASSCF and CASPT2 level, including an accurate description of the critical configurations, such as minima and transition states. The chosen active space and the CASSCF/CASPT2 computational protocol are assessed against coupled-cluster calculations to further check the stability and reliability of the entire multiconfigurational procedure.

222 Rn emanation measurements for the XENON1T experiment

The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the 222 Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a 222 Rn activity concentration of 10 μ Bq / kg in 3.2 t of xenon. The knowledge of the distribution of the 222 Rn sources allowed us to selectively eliminate problematic components in the course of the experiment. The predictions from the emanation measurements were compared to data of the 222 Rn activity concentration in XENON1T. The final 222 Rn activity concentration of ( 4.5 ± 0.1 ) μ Bq / kg in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment.

Choice of access route for artificial nutrition in cancer patients: 30 y of activity in a home palliative care setting

OBJECTIVES

Malnutrition negatively affects the quality of life, survival, and clinical outcome of patients with cancer. Home artificial nutrition (HAN) is an appropriate nutritional therapy to prevent death from cachexia and to improve quality of life, and it can be integrated into a home palliative care program. The choice to start home enteral nutrition (HEN) or home parenteral nutrition (HPN) is based on patient-specific indications and contraindications. The aim of this observational study was to analyze the changes that occurred in the criteria for choosing the access route to artificial nutrition during 30 y of activity of a nutritional service team (NST) in a palliative home care setting, as well as to compare indications, clinical nutritional outcomes, and complications between HEN and HPN.

METHODS

The following parameters were analyzed and compared for HEN and HPN: tumor site and metastases; nutritional status (body mass index, weight loss in the past 6 mo); basal energy expenditure and oral food intake; Karnofsky performance status; access routes to HEN (feeding tubes) and HPN (central venous catheters); water and protein-calorie support; and survival and complications of HAN.

RESULTS

From 1990 to 2020, HAN was started in 1014 patients with cancer (592 men, 422 women; 65.6 ± 12.7 y of age); HPN was started in 666 patients (66%); and HEN was started in 348 patients (34%). At the end of the study, 921 patients had died, 77 had suspended HAN for oral refeeding and 16 were in the progress of HAN. The oral caloric intake was <50% basal energy expenditure in all patients: 721 (71.1%) were unable to eat at all (HEN 270, HPN 451), whereas in 293 patients (28.9%), artificial nutrition was supplementary to oral intake. From 2010 to 2020, the number of central venous catheters for HPN, especially peripherally inserted central catheters, doubled compared with that in the previous 20 y, with a decrease of 71.6% in feeding tubes for HEN. At the beginning, patients on HEN and HPN had comparable nutrition and performance status, and there was no difference in nutritional outcome after 1 mo of HAN. In 215 patients who started supplemental parenteral nutrition to oral feeding, total protein-calorie intake allowed a significant increase in body mass index and Karnofsky performance status. The duration of HEN was longer than that of HPN but was similar to that of supplemental parenteral nutrition.

CONCLUSIONS

Over 30 y of nutritional service team activity, the choice of central venous catheters as an access route to HAN increased progressively and significantly due to personalized patient decision-making choices. Nutritional efficacy was comparable between HEN and HPN. In patients who maintained food oral intake, supplemental parenteral nutrition improved weight, performance status, and survival better than other types of HAN.

Suggestions for changes in professional procedures and adaptation to COVID-19: new models of care in the rehabilitation setting

Abstracts

The COVID-19 (COrona Virus Disease 2019), due to the SARS-COV-2 (Severe Acute Respiratory Syndrome Corona Virus 2) has been an unprecedented global challenge for the healthcare systems (1).

Quantum-classical nonadiabatic dynamics of Floquet driven systems

We develop a trajectory-based approach for excited-state molecular dynamics simulations of systems subject to an external periodic drive. We combine the exact-factorization formalism, allowing us to treat electron-nuclear systems in nonadiabatic regimes, with the Floquet formalism for time-periodic processes. The theory is developed starting with the molecular time-dependent Schrödinger equation with the inclusion of an external periodic drive that couples to the system dipole moment. With the support of the Floquet formalism, quantum dynamics is approximated by combining classical-like, trajectory-based, nuclear evolution with electronic dynamics represented in the Floquet basis. The resulting algorithm, which is an extension of the coupled-trajectory mixed quantum-classical scheme for periodically driven systems, is applied to a model study, exactly solvable, with different field intensities.

Search for Coherent Elastic Scattering of Solar ^{8}B Neutrinos in the XENON1T Dark Matter Experiment

We report on a search for nuclear recoil signals from solar ^{8}B neutrinos elastically scattering off xenon nuclei in XENON1T data, lowering the energy threshold from 2.6 to 1.6  keV. We develop a variety of novel techniques to limit the resulting increase in backgrounds near the threshold. No significant ^{8}B neutrinolike excess is found in an exposure of 0.6  t×y. For the first time, we use the nondetection of solar neutrinos to constrain the light yield from 1-2 keV nuclear recoils in liquid xenon, as well as nonstandard neutrino-quark interactions. Finally, we improve upon world-leading constraints on dark matter-nucleus interactions for dark matter masses between 3 and 11  GeV c^{-2} by as much as an order of magnitude.

Multiomics Analysis Provides Insight into the Laboratory Evolution of Escherichia coli toward the Metabolic Usage of Fluorinated Indoles

Organofluorine compounds are known to be toxic to a broad variety of living beings in different habitats, and chemical fluorination has been historically exploited by mankind for the development of therapeutic drugs or agricultural pesticides. On the other hand, several studies so far have demonstrated that, under appropriate conditions, living systems (in particular bacteria) can tolerate the presence of fluorinated molecules (e.g., amino acids analogues) within their metabolism and even repurpose them as alternative building blocks for the synthesis of cellular macromolecules such as proteins. Understanding the molecular mechanism behind these phenomena would greatly advance approaches to the biotechnological synthesis of recombinant proteins and peptide drugs. However, information about the metabolic effects of long-term exposure of living cells to fluorinated amino acids remains scarce. Hereby, we report the long-term propagation of Escherichia coli (E. coli) in an artificially fluorinated habitat that yielded two strains naturally adapted to live on fluorinated amino acids. In particular, we applied selective pressure to force a tryptophan (Trp)-auxotrophic strain to use either 4- or 5-fluoroindole as essential precursors for the in situ synthesis of Trp analogues, followed by their incorporation in the cellular proteome. We found that full adaptation to both fluorinated Trp analogues requires a low number of genetic mutations but is accompanied by large rearrangements in regulatory networks, membrane integrity, and quality control of protein folding. These findings highlight the cellular mechanisms behind the adaptation to unnatural amino acids and provide the molecular foundation for bioengineering of novel microbial strains for synthetic biology and biotechnology.

Relaxation dynamics through a conical intersection: Quantum and quantum-classical studies

We study the relaxation process through a conical intersection of a photo-excited retinal chromophore model. The analysis is based on a two-electronic-state two-dimensional Hamiltonian developed by Hahn and Stock [J. Phys. Chem. B 104 1146 (2000)] to reproduce, with a minimal model, the main features of the 11-cis to all-trans isomerization of the retinal of rhodopsin. In particular, we focus on the performance of various trajectory-based schemes to nonadiabatic dynamics, and we compare quantum-classical results to the numerically exact quantum vibronic wavepacket dynamics. The purpose of this work is to investigate, by analyzing electronic and nuclear observables, how the sampling of initial conditions for the trajectories affects the subsequent dynamics.

Quantum and Quantum-Classical Studies of the Photoisomerization of a Retinal Chromophore Model

We report an in-depth analysis of the photo-induced isomerization of the 2-cis-penta-2,4-dieniminium cation: a minimal model of the 11-cis retinal protonated Schiff base chromophore of the dim-light photoreceptor rhodopsin. Based on recently developed three-dimensional potentials parametrized on ab initio multi-state multi-configurational second-order perturbation theory data, we perform quantum-dynamical studies. In addition, simulations based on various quantum-classical methods, among which Tully surface hopping and the coupled-trajectory approach derived from the exact factorization, allow us to validate their performance against vibronic wavepacket propagation and, therefore, a purely quantum treatment. Quantum-dynamics results uncover qualitative differences with respect to the two-dimensional Hahn-Stock potentials, widely used as model potentials for the isomerization of the same chromophore, due to the increased dimensionality and three-mode correlation. Quantum-classical simulations show, instead, that three-dimensional model potentials are capable of capturing a number of features revealed by atomistic simulations and experimental observations. In particular, a recently reported vibrational phase relationship between double-bond torsion and hydrogen-out-of-plane modes critical for rhodopsin isomerization efficiency is correctly reproduced.

Quantum Trajectories for the Dynamics in the Exact Factorization Framework: A Proof-of-Principle Test

In the framework of the exact factorization of the time-dependent electron-nuclear wave function, we investigate the possibility of solving the nuclear time-dependent Schrödinger equation based on trajectories. The nuclear equation is separated in a Hamilton-Jacobi equation for the phase of the wave function, and a continuity equation for its (squared) modulus. For illustrative adiabatic and nonadiabatic one-dimensional models, we implement a procedure to follow the evolution of the nuclear density along the characteristics of the Hamilton-Jacobi equation. Those characteristics are referred to as quantum trajectories, since they are generated via ordinary differential equations similar to Hamilton's equations, but including the so-called quantum potential, and they can be used to reconstruct exactly the quantum-mechanical nuclear wave function, provided infinite initial conditions are propagated in time.

Internal Conversion and Intersystem Crossing with the Exact Factorization

We present a detailed derivation of the generalized coupled-trajectory mixed quantum-classical (G-CT-MQC) algorithm based on the exact-factorization equations. The ultimate goal is to propose an algorithm that can be employed for molecular dynamics simulations of nonradiative phenomena, as the spin-allowed internal conversions and the spin-forbidden intersystem crossings. Internal conversions are nonadiabatic processes driven by the kinetic coupling between electronic states, whereas intersystem crossings are mediated by the spin-orbit coupling. In this paper, we discuss computational issues related to the suitable representation for electronic dynamics and the different natures of kinetic and spin-orbit coupling. Numerical studies on model systems allow us to test the performance of the G-CT-MQC algorithm in different situations.

Ultra-High-Throughput Clinical Proteomics Reveals Classifiers of COVID-19 Infection

The COVID-19 pandemic is an unprecedented global challenge, and point-of-care diagnostic classifiers are urgently required. Here, we present a platform for ultra-high-throughput serum and plasma proteomics that builds on ISO13485 standardization to facilitate simple implementation in regulated clinical laboratories. Our low-cost workflow handles up to 180 samples per day, enables high precision quantification, and reduces batch effects for large-scale and longitudinal studies. We use our platform on samples collected from a cohort of early hospitalized cases of the SARS-CoV-2 pandemic and identify 27 potential biomarkers that are differentially expressed depending on the WHO severity grade of COVID-19. They include complement factors, the coagulation system, inflammation modulators, and pro-inflammatory factors upstream and downstream of interleukin 6. All protocols and software for implementing our approach are freely available. In total, this work supports the development of routine proteomic assays to aid clinical decision making and generate hypotheses about potential COVID-19 therapeutic targets.

Trade-Offs with rehabilitation Effectiveness (REs) and Efficiency (REy) in a sample of Italian disabled persons in a in post-acuity rehabilitation unit

BACKGROUND

Intensive Rehabilitation Centres, known in Italy as "code 56", admit patients who need to recover from an acute episode. Different Rehabilitation Impact Indices have been proposed as composite rehabilitation outcomes measuring the rate of improvement due to a rehabilitation program. The most widely employed measure the performance of Activities of daily living in rehabilitation is the modified Barthel Index. The Barthel Index-based Rehabilitation Impact Indices are the Rehabilitation Effectiveness and the Rehabilitation Efficiency.

AIM

The aim of our study was to evaluate the trade-off between Rehabilitation Effectiveness tayand Rehabilitation Efficiency with respect to the Barthel Index admission score and the Length Of Stay, and their ideal ranges that optimized both indices.

METHODS

We retrospectively evaluated data of all patients admitted to intensive rehabilitation unit of the Scientific Institute for Research and Healthcare San Raffaele Pisana of Rome, from January 2006 to March 2018. The primary outcome measures of our study were patient's Rehabilitation Effectiveness and Rehabilitation Efficiency during the hospital stay.

RESULTS

A database of 3,466 patients was analysed and the Rehabilitation Effectiveness and Rehabilitation Efficiency indexes were calculated. We calculated the median rank ratio of the Rehabilitation Effectiveness to the Rehabilitation Efficiency against Barthel Index scores. We calculated the median rank ratio of the Rehabilitation Effectiveness to Rehabilitation Efficiency against Barthel Index scores and days of stay. The median rank ratio of the Rehabilitation Effectiveness to the Rehabilitation Efficiency value were 1 in the range of Barthel Index scores from 32 to 42. The median rank ratio of the Rehabilitation Effectiveness to Rehabilitation Efficiency value were 1 for a Length of Stay corresponding to 33 days.

CONCLUSIONS

In our study we calculated the Trade-offs between Rehabilitation Effectiveness and Rehabilitation Efficiency with respect to admission Barthel Index Score and Length Of Stay in a population of 3,466 patients affected by orthopedic (1,707) and neurological (1,759) diseases. Every member of the healthcare team should be aware of such trade-offs when they make decisions about rehabilitation services.

Idiopathic facial palsy: umbrella review of systematic reviews and meta-analyses

Idiopathic facial palsy is the most common disease of the VII cranial nerve. There are many treatments to facilitate recovery from this condition: pharmacological, surgical, rehabilitative, but the effectiveness of some of these treatments, especially the latter, is still under discussion. The purpose of this umbrella review of systematic reviews is to analyse the literature in order to investigate the different rehabilitation interventions in patients suffering from idiopathic facial palsy. A scientific literature search was carried out from January 2009 until August 2019, using Mesh the terms "facial palsy", "Bell's Palsy", "idiopathic facial nerve palsy", combined with "rehabilitation" and "therapy". Initially all the systematic reviews and meta-analyses of the last 10 years concerning rehabilitation treatments for the recovery of injured functions in facial palsy were included. Given the heterogeneity of the studies in the literature, which do not differentiate the different causes of facial palsy, all the causes of idiopathic facial palsy were included in the review. The research resulted in 94 published systematic reviews but only 6 were considered in respect to the inclusion criteria. All studies agree on the lack of high-quality scientific work to be able to say that Bell's physiotherapy treatments for facial palsy are effective, in particular with regard to recovery times during the rehabilitation process. Future studies are needed, in order to highlight the therapeutic implications of the different rehabilitation methods, with standardized protocols, in patients suffering from facial palsy of different aetiology.

Spin-Orbit Interactions in Ultrafast Molecular Processes

We investigate spin-orbit interactions in ultrafast molecular processes employing the exact factorization of the electron-nuclear wave function. We revisit the original derivation by including spin-orbit coupling, and show how the dynamics driven by the time-dependent potential energy surface alleviates inconsistencies arising from different electronic representations. We propose a novel trajectory-based scheme to simulate spin-forbidden non-radiative processes, and we show its performance in the treatment of excited-state dynamics where spin-orbit effects couple different spin multiplets.

Light Dark Matter Search with Ionization Signals in XENON1T

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4  keV_{ee}, we observe <1  event/(tonne day keV_{ee}), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m_{χ} within 3-6  GeV/c^{2}, DM-electron scattering for m_{χ}>30  MeV/c^{2}, and absorption of dark photons and axionlike particles for m_{χ} within 0.186-1  keV/c^{2}.

Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.