The XDEM Multi-physics and Multi-scale Simulation Technology: Review on DEM-CFD Coupling, Methodology and Engineering Applications

The XDEM multi-physics and multi-scale simulation platform roots in the Ex- tended Discrete Element Method (XDEM) and is being developed at the In- stitute of Computational Engineering at the University of Luxembourg. The platform is an advanced multi- physics simulation technology that combines flexibility and versatility to establish the next generation of multi-physics and multi-scale simulation tools. For this purpose the simulation framework relies on coupling various predictive tools based on both an Eulerian and Lagrangian approach. Eulerian approaches represent the wide field of continuum models while the Lagrange approach is perfectly suited to characterise discrete phases. Thus, continuum models include classical simulation tools such as Computa- tional Fluid Dynamics (CFD) or Finite Element Analysis (FEA) while an ex- tended configuration of the classical Discrete Element Method (DEM) addresses the discrete e.g. particulate phase. Apart from predicting the trajectories of individual particles, XDEM extends the application to estimating the thermo- dynamic state of each particle by advanced and optimised algorithms. The thermodynamic state may include temperature and species distributions due to chemical reaction and external heat sources. Hence, coupling these extended features with either CFD or FEA opens up a wide range of applications as diverse as pharmaceutical industry e.g. drug production, agriculture food and processing industry, mining, construction and agricultural machinery, metals manufacturing, energy production and systems biology

The role of the dental surgeon in the early diagnosis of oral cancer: a concise systematic review

Introduction: Oral cancers (OC) represent more than 90% of cases. It is estimated that more than 400,000 new cases of oral cancer are diagnosed each year worldwide. OC is preventable as most of the different identified risk factors, such as tobacco use, alcohol consumption, and betel nut chewing, are behaviors that increase the likelihood of the disease. Surgical biopsy remains the gold standard, but adjunctive tools have been developed to aid diagnoses, such as vital toluidine blue staining and autofluorescence imaging. Objective: To emphasize and present the importance of the dental surgeon in the early diagnosis and prevention of oral cancer. Methods: The survey was conducted from July 2021 to August 2021 and developed based on Scopus, PubMed, Science Direct, Scielo, and Google Scholar, following the rules of Systematic Review-PRISMA. Study quality was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results: Early detection and treatment of OC were found to be important predictors for improving survival and reducing mortality. A thorough clinical inspection of the oral cavity can detect up to 99% of oral cancers. Other diagnostic types have been developed to help overcome the limits of standard oral clinical examination, highlighting toluidine blue staining, light-based detection techniques, and salivary biomarkers. Self-examination is an effective strategy to reduce the levels of mortality and morbidity caused by this pathology. A gain of 8.09% more in sensitivity and 11.36% more in specificity was observed with the fluorescence test. Conclusion: The findings clearly showed that early diagnosis of oral cancer is essential to increase the chances of cure and survival of patients, avoiding invasive surgical intervention. Currently, there are several diagnostic tools for screening and visual devices for the early detection of oral lesions through auxiliary methods, logically maintaining biopsy as the gold standard

Variational approach to interpolate and correct biases in stereo correlation

Un défaut bien connu des modèles numériques d 'élévation (MNE) obtenus par des techniques de corrélation, est le phénomène d'adhérence, qui apparaît le long des bords très contrastés de l'image comme une dilatation de la partie supérieure (ou inférieure) du terrain estimé. Le phénomène est directement lié à la taille des voisinages utilisés lors de la maximisation de la corrélation normalisée, et la magnitude de ces artefacts ne peut pas être négligée quand une précision très sous-pixellaire est cherchée. Le travail de Delon et Rougé [3] donne une caractérisation de ce phénomène, fournissant un lien entre les disparités mesurées par corrélation et les vraies disparités. Il permet aussi de détecter des régions incorrélables, c'est à dire, des régions ne contenant aucune information utile pour une corrélation suffisamment précise. Comme cette relation (entre disparités vraies et estimées) est exprimée par un système linéaire très mal posé, des nombreuses suppositions simplificatrices ont été adoptées pour sa résolution, conduisant à la correction barycentrique du phénomène d'adhérence. Le résultat, bien que beaucoup amélioré par rapport aux disparités brutes, reste légèrement flou et oscillant, ce qui est particulièrement gênant pour le MNE urbain. Dans cet article nous proposons des suppositions simplificatrices moins contraignantes pour l'inversion du système, à savoir, sa régularisation par un terme de surface minimale ou variation totale. Une telle approche permet d'obtenir un terrain avec des bords moins flous, tout en interpolant les régions vides (sans information fiable de corrélation) d'une façon raisonnable

The relationship between caregiver contribution to self-care and patient quality of life in heart failure: A longitudinal mediation analysis

Background: Patients with heart failure may experience poor quality of life due to a variety of physical and psychological symptoms. Quality of life can improve if patients adhere to consistent self-care behaviors. Patient outcomes (i.e., quality of life) are thought to improve as a result of caregiver contribution to self-care. However, uncertainty exists on whether these outcomes improve as a direct result of caregiver contribution to self-care or whether this improvement occurs indirectly through the improvement of patient heart failure self-care behaviors. Aims: To investigate the influence of caregiver contribution to self-care on quality of life of heart failure people and explore whether patient self-care behaviors mediate such a relationship. Methods: This is a secondary analysis of the MOTIVATE-HF randomized controlled trial (Clinicaltrials.gov registration number: NCT02894502). Data were collected at baseline and 3 months. An autoregressive longitudinal path analysis model was conducted to test our hypotheses. Results: We enrolled a sample of 510 caregivers [mean age = 54 (±15.44), 24% males)] and 510 patients [mean age = 72.4 (±12.28), 58% males)]. Patient self-care had a significant and direct effect on quality of life at three months (β = 0.20, p < .01). Caregiver contribution to self-care showed a significant direct effect on patient self-care (β = 0.32, p < .01), and an indirect effect on patient quality of life through the mediation of patient self-care (β = 0.07, p < .001). Conclusion: Patient quality of life is influenced by self-care both directly and indirectly, through the mediation of caregiver contribution to self-care. These findings improve our understanding on how caregiver contribution to self-care improves patient outcomes

Traumatic brain injury modifies the relationship between physical activity and global and cognitive health : Results from the barcelona brain health initiative

Physical activity has many health benefits for individuals with and without history of brain injury. Here, we evaluated in a large cohort study the impact of physical activity on global and cognitive health as measured by the PROMIS global health and NeuroQoL cognitive function questionnaires. A nested case control study assessed the influence of a history of traumatic brain injury (TBI) on the effects of physical activity since underlying pathophysiology and barriers to physical activity in individuals with TBI may mean the effects of physical activity on perceived health outcomes differ compared to the general population. Those with a history of TBI (n = 81) had significantly lower Global health (β = −1.66, p = 0.010) and NeuroQoL cognitive function (β = −2.65, p = 0.006) compared to healthy adults (n = 405). A similar proportion of individuals in both groups reported being active compared to being insufficiently active ((Formula presented.) = 0.519 p = 0.471). Furthermore, the effect of physical activity on global health (β = 0.061, p = 0.076) and particularly for NeuroQoL (β = 0.159, p = 0.002) was greater in those with a history of TBI. Individuals with a history of TBI can adhere to a physically active lifestyle, and if so, that is associated with higher global and cognitive health perceptions. Adhering to a physically active lifestyle is non-trivial, particularly for individuals with TBI, and therefore adapted strategies to increase participation in physical activity is critical for the promotion of public health

Meaning in life: resilience beyond reserve

Background: The contribution of psychological factors to brain health and resilience remains poorly investigated. Furthermore, their possible interaction with ‘classical’ cognitive reserve (CR) estimates in predicting perceived mental health and cognitive status has not been specifically addressed. Methods: We obtained data from 1081 adults responding to questionnaires on the three meaning in life (MiL) dimensions: purpose in life (PiL), sense of coherence (SoC), and engagement with life (EwL). A questionnaire on CR variables was also administered. The outcome measures were self-reported cognitive function and affective status (depression, stress, and anxiety). Multiple linear regression analyses were used to evaluate the association between sociodemographic variables, MiL dimensions, and CR with the two selected outcomes. Mediation analyses, adjusted for age and gender, were applied to determine whether the MiL dimensions mediated the putative effects of CR on self-reported mental and cognitive health. Results: All three MiL components, but not CR estimates, correlated with the self-reported affective status of the participants. Higher CR, PiL, and SoC (but not EwL) scores significantly correlated with higher perceived cognitive function. Notably, the observed association between the CR measures and self-reported cognitive function was mediated by PiL and SoC. Conclusions: Psychological MiL dimensions mediate the association between classic CR estimates and self-perceived cognitive function. Further studies on CR could consider including formal measures of such psychological factors to better understand their unique or synergistic contributions, as well as investigate the associated mechanisms maintaining brain function at older ages. Electronic supplementary material The online version of this article (10.1186/s13195-018-0381-z) contains supplementary material, which is available to authorized users

Tele-supervised home-based transcranial alternating current stimulation (tACS) for Alzheimer’s disease: a pilot study

BackgroundOver 55 million people worldwide are currently diagnosed with Alzheimer’s disease (AD) and live with debilitating episodic memory deficits. Current pharmacological treatments have limited efficacy. Recently, transcranial alternating current stimulation (tACS) has shown memory improvement in AD by normalizing high-frequency neuronal activity. Here we investigate the feasibility, safety, and preliminary effects on episodic memory of an innovative protocol where tACS is administered within the homes of older adults with AD with the help of a study companion (HB-tACS).MethodsEight participants diagnosed with AD underwent multiple consecutive sessions of high-definition HB-tACS (40 Hz, 20-min) targeting the left angular gyrus (AG), a key node of the memory network. The Acute Phase comprised 14-weeks of HB-tACS with at least five sessions per week. Three participants underwent resting state electroencephalography (EEG) before and after the 14-week Acute Phase. Subsequently, participants completed a 2–3-month Hiatus Phase not receiving HB-tACS. Finally, in the Taper phase, participants received 2–3 sessions per week over 3-months. Primary outcomes were safety, as determined by the reporting of side effects and adverse events, and feasibility, as determined by adherence and compliance with the study protocol. Primary clinical outcomes were memory and global cognition, measured with the Memory Index Score (MIS) and Montreal Cognitive Assessment (MoCA), respectively. Secondary outcome was EEG theta/gamma ratio. Results reported as mean ± SD.ResultsAll participants completed the study, with an average of 97 HB-tACS sessions completed by each participant; reporting mild side effects during 25% of sessions, moderate during 5%, and severe during 1%. Acute Phase adherence was 98 ± 6.8% and Taper phase was 125 ± 22.3% (rates over 100% indicates participants completed more than the minimum of 2/week). After the Acute Phase, all participants showed memory improvement, MIS of 7.25 ± 3.77, sustained during Hiatus 7.00 ± 4.90 and Taper 4.63 ± 2.39 Phases compared to baseline. For the three participants that underwent EEG, a decreased theta/gamma ratio in AG was observed. Conversely, participants did not show improvement in the MoCA, 1.13 ± 3.80 after the Acute Phase, and there was a modest decrease during the Hiatus −0.64 ± 3.28 and Taper −2.56 ± 5.03 Phases.ConclusionThis pilot study shows that the home-based, remotely-supervised, study companion administered, multi-channel tACS protocol for older adults with AD was feasible and safe. Further, targeting the left AG, memory in this sample was improved. These are preliminary results that warrant larger more definite trials to further elucidate tolerability and efficacy of the HB-tACS intervention. NCT04783350.Clinical trial registrationhttps://clinicaltrials.gov/ct2/show/NCT04783350?term=NCT04783350&draw=2&rank=1, identifier NCT04783350

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline

BackgroundWith our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.MethodsFifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes.ResultsOverall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d <0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p < 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d < 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p < 0.001), with remote participants demonstrating greater exercise engagement than in-person participants.ConclusionImprovements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement

Local Prefrontal Cortex TMS-Induced Reactivity Is Related to Working Memory and Reasoning in Middle-Aged Adults

Introduction: The prefrontal cortex (PFC) plays a crucial role in cognition, particularly in executive functions. Cortical reactivity measured with Transcranial Magnetic Stimulation combined with Electroencephalography (TMS-EEG) is altered in pathological conditions, and it may also be a marker of cognitive status in middle-aged adults. In this study, we investigated the associations between cognitive measures and TMS evoked EEG reactivity and explored whether the effects of this relationship were related to neurofilament light chain levels (NfL), a marker of neuroaxonal damage. Methods: Fifty two healthy middle-aged adults (41–65 years) from the Barcelona Brain Health Initiative cohort underwent TMS-EEG, a comprehensive neuropsychological assessment, and a blood test for NfL levels. Global and Local Mean-Field Power (GMFP/LMFP), two measures of cortical reactivity, were quantified after left prefrontal cortex (L-PFC) stimulation, and cognition was set as the outcome of the regression analysis. The left inferior parietal lobe (L-IPL) was used as a control stimulation condition. Results: Local reactivity was significantly associated with working memory and reasoning only after L-PFC stimulation. No associations were found between NfL and cognition. These specific associations were independent of the status of neuroaxonal damage indexed by the NfL biomarker and remained after adjusting for age, biological sex, and education. Conclusion: Our results demonstrate that TMS evoked EEG reactivity at the L-PFC, but not the L-IPL, is related to the cognitive status of middle-aged individuals and independent of NfL levels, and may become a valuable biomarker of frontal lobe-associated cognitive function

Engineered In vitro Models for Pathological Calcification: Routes Toward Mechanistic Understanding

Physiological calcification plays an essential part in the development of the skeleton and teeth; however, the occurrence of calcification in soft tissues such as the brain, heart, and kidneys associates with health impacts, creating a massive social and economic burden. The current paradigm for pathological calcification focuses on the biological factors responsible for bone-like mineralization, including osteoblast-like cells and proteins inducing nucleation and crystal growth. However, the exact mechanism responsible for calcification remains unknown. Toward this goal, this review dissects the current understanding of structure–function relationships and physico-chemical properties of pathologic calcification from a materials science point of view. We will discuss a range of potential mechanisms of pathological calcification, with the purpose of identifying universal mechanistic pathways that occur across multiple organs/tissues at multiple length scales. The possible effect of extracellular components in signaling and templating mineralization, as well as the role of intrinsically disordered proteins in calcification, is reviewed. The state-of-the-art in vitro models and strategies that can recreate the highly dynamic environment of calcification are identified