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Background Research shows that older adults' performance on choice reaction time (CRT) tests can predict cognitive decline. A simple CRT tool could help detect mild cognitive impairment (MCI) and preclinical dementia, allowing for further stratification of cognitive disorders on-site or via telemedicine. Objective The primary objective was to develop a CRT testing device and protocol to differentiate between two cognitive impairment categories: (a) subjective cognitive decline (SCD) and non-amnestic mild cognitive impairment (na-MCI), and (b) amnestic mild cognitive impairment (a-MCI) and multiple-domain a-MCI (a-MCI-MD). Methods A pilot study in Italy and Romania with 35 older adults (ages 61–85) assessed cognitive function using the Mini-Mental State Examination (MMSE) and a CRT color response task. Reaction time, accuracy, and demographics were recorded, and machine learning classifiers analyzed performance differences to predict preclinical dementia and screen for mild cognitive deficits. Results Moderate correlations were found between the MMSE score and both mean reaction time and mean accuracy rate. There was a significant difference between the two groups’ reaction time for blue light, but not for any other colors or for mean accuracy rate. SVM and RUSBoosted trees were found to have the best preclinical dementia prediction capabilities among the tested classifier algorithms, both presenting an accuracy rate of 77.1%. Conclusions CRT testing with machine learning effectively differentiates cognitive capacities in older adults, facilitating early diagnosis and stratification of neurocognitive diseases and can also identify impairments from stressors like dehydration and sleep deprivation. This study highlights the potential of portable CRT devices for monitoring cognitive function, including SCD and MCI.

BackgroundLoneliness and social isolation are major public health concerns for older adults, with severe mental and physical health consequences. New technologies may have a great impact in providing support to the daily lives of older adults and addressing the many challenges they face. In this scenario, technologies based on voice assistants (VAs) are of great interest and potential benefit in reducing loneliness and social isolation in this population, because they could overcome existing barriers with other digital technologies through easier and more natural human-computer interaction. ObjectiveThis study aims to investigate the use of VAs to reduce loneliness and social isolation of older adults by performing a systematic literature review and a bibliometric cluster mapping analysis. MethodsWe searched PubMed, Embase, and Scopus databases for articles that were published in the last 6 years, related to the following main topics: voice interface, VA, older adults, isolation, and loneliness. A total of 40 articles were found, of which 16 (40%) were included in this review. The included articles were then assessed through a qualitative scoring method and summarized. Finally, a bibliometric analysis was conducted using VOSviewer software (Leiden University’s Centre for Science and Technology Studies). ResultsOf the 16 articles included in the review, only 2 (13%) were considered of poor methodological quality, whereas 9 (56%) were of medium quality and 5 (31%) were of high quality. Finally, through bibliometric analysis, 221 keywords were extracted, of which 36 (16%) were selected. The most important keywords, by number of occurrences and by total link strength; results of the analysis with the Association Strength normalization method; and default values were then presented. The final bibliometric network consisted of 36 selected keywords, which were grouped into 3 clusters related to 3 main topics (ie, VA use for social isolation among older adults, the significance of age in the context of loneliness, and the impact of sex factors on well-being). For most of the selected articles, the effect of VA on social isolation and loneliness of older adults was a minor theme. However, more investigations were done on user experience, obtaining preliminary positive results. ConclusionsMost articles on the use of VAs by older adults to reduce social isolation and loneliness focus on usability, acceptability, or user experience. Nevertheless, studies directly addressing the impact that using a VA has on the social isolation and loneliness of older adults find positive and promising results and provide important information for future research, interventions, and policy development in the field of geriatric care and technology.

A wide band gap semiconductor power module can operate at higher voltages as compared with its traditional silicon counterpart. However, its insulating system undergoes stronger electric fields at the triple point between the ceramic substrate, the metallic tracks and the encapsulating polymer, which can dramatically reduce its lifespan. Here we report an original concept based on the local modification of the substrate properties to mitigate such electrical stress. Numerical simulations revealed its potential to reduce this constraint by up to 50%. This concept was realized by developing, through a practical approach, a novel substrate made of an AlN-based ceramic (material A) integrating a nanocomposite volume endowed with controlled properties and geometry. This approach implies first the spark plasma sintering of the AlN powder with additives (Y2O3, CaF2) to endow the material A with a very low electrical conductivity (σ) and high thermal conductivity (k). Graphene nanoplatelets (GNP) were incorporated within this material to fabricate a nanocomposite with a controlled σ anisotropy that otherwise reached a striking ratio of 106 at 20°C for 1.25 vol% GNP. Our approach secondly aimed at developing an effective process allowing to integrate this nanocomposite into the material A with a very high degree of reproducibility. It finally consisted in establishing the electrical contacts on the achieved substrate and encapsulating it for breakdown testing. The novel substrate enabled a mitigation of the electrical constraint by diminishing its intensity and shifting it from the triple point to a less constrained area. It already brought an improvement in breakdown voltage (VB) by 15% as compared to the traditional substrate, and revealed the potential for achieving higher VB as well. This work lays the foundation for the development of novel multifunctional ceramic-matrix composite substrates sought for power electronics as well as for other potential applications.

Patients harboring homozygous c.498_499insC mutations in MFRP demonstrate hyperopia, microphthalmia, retinitis pigmentosa, retinal pigment epithelial atrophy, variable degrees of foveal edema, and optic disc drusen. The disease phenotype is variable, however, with some patients maintaining good central vision and cone function till late in the disease. A knock-in mouse model with the c.498_499insC mutation in Mfrp (Mfrp KI/KI) was developed to understand the effects of these mutations in the retina. The model shares many of the features of human clinical disease, including reduced axial length, hyperopia, retinal degeneration, retinal pigment epithelial atrophy, and decreased electrophysiological responses. In addition, the eyes of these mice had a significantly greater refractive error (p

It is shown that when adding a large number to a set of much smaller numbers, the number of primes or twin ranks (see text) in the resulted sumset can be substantially larger than the theoretical values given by the Prime Number Theorem or Hardy-Littlewood Conjecture. Specifically, the ratios of the observed numbers of primes or twin ranks to the calculated values are proportional to the logarithm and, respectively, logarithm squared of the prime omega function of the large number. A consequence of this characteristic is the existence in the set of positive integers of an infinite number of intervals where all primes or twin ranks are separated from a certain number inside by distances that are primes or twin ranks.

Biodegradable and biocompatible polymers represent an excellent alternative to conventional polymers for various applications. One of the most promising biopolymers is represented by polylactic acid (PLA). During injection molding process, the cooling stage has a great importance because it ensures the dimensional stability of the produced articles. In this simulation study regarding the cooling process in the injection molding of PLA, with cold water, it was analyzed the temperature distribution in the mold-material system in the case of a polymeric plate and the cooling time was calculated. The model of heat transfer was solved in COMSOL Multiphysics software, by defining the geometry of the mold, the materials properties and the cooling conditions. [ABSTRACT FROM AUTHOR]

Model-based evaluation of major accident consequences and effects occurring during the transport of dangerous substances presents a great interest, because it allows derivation of relevant conclusions on the cause-effect close relationship. Such a numerical (in-silico) analysis helps to improve safety regulations for the transport of hazardous substances aimed at preventing dramatic accidents causing many deaths, injuries, and structural damage. By using the standard TNT equivalency math model, coupled with the Probit functions technique, the consequences and effects of an accidental blast have been estimated.1,2 The approached case study here refers to the accidental explosion of a truck while transporting 20 t of ammonium nitrate (AN) in the proximity of Mihăileşti village (Romania) on 24 May 2004. The model-based simulated accident consequences and effects match the data taken on the spot after the accident. Multiple simulations lead to deriving relevant conclusions of practiced value for improving the transport safety of hazardous substances.

Long-duration space flight missions impose extreme physiological stress and/or changes, such as musculoskeletal function degradation, on the crew due to the microgravity exposure. A great deal of research studies have been conducted in order to understand these physiological stress influences and to provide countermeasures to minimize the observed negative effects of weightlessness exposure on musculoskeletal function. Among others, studies and experiments have been conducted in DI analogue Earth-based facilities in order to reproduce the weightlessness negative effects on the human body. This paper presents a complex muscular analysis of mechanical wave propagation in striated muscle, using MusTone, a device developed in-house at the Institute of Space Science, Romania. The data were collected during a 21-day DI campaign in order to investigate muscle fibers’ behavior in longitudinal direction, after applying a mechanical impulse, taking into account two particular parameters, namely propagation velocity and amortization ratio. The parameters were determined based on the wave-propagation data collected from five points (one impact point, two distal direction points, and two proximal direction points) along the muscle fiber. By statistically analyzing propagation velocity and amortization ratio parameters, the study revealed that muscle deconditioning is time dependent, the amortization ratio is more significant in the distal direction, and the lower fibers are affected the most.

Chitosan is a natural polymer with numerous biomedical applications. The cellular activity of chitosan has been studied in various types of cancer, including melanoma, and indicates that these molecules can open new perspectives on antiproliferative action and anticancer therapy. This study analyzes how different chitosan conformations, such as α-chitosan (CH) or β-oligochitosan (CO), with various degrees of deacetylation (DDA) and molar mass (MM), both in different concentrations and in CH–CO mixtures, influence the cellular processes of SK-MEL-28 melanocytes, to estimate the reactivity of these cells to the applied treatments. The in vitro evaluation was carried out, aiming at the cellular metabolism (MTT assay), cellular morphology, and chitinase-like glycoprotein YKL-40 expression. The in vitro effect of the CH–CO mixture application on melanocytes is obvious at low concentrations of α-chitosan/β-oligochitosan (1:2 ratio), with the cell's response supporting the hypothesis that β-oligo-chitosan amplifies the effect. This oligochitosan mixture, favored by the β conformation and its small size, penetrates faster into the cells, being more reactive when interacting with some cellular components. Morphological effects expressed by the loss of cell adhesion and the depletion of YKL-40 synthesis are significant responses of melanocytes. β-oligochitosan (1.5 kDa) induces an extension of cytophysiological effects and limits the cell viability compared to α-chitosan (400–900 kDa). Statistical analysis using multivariate techniques showed differences between the CH samples and CH–CO mixtures. [ABSTRACT FROM AUTHOR]

This paper is about a class of numbers indirectly connected to the twin primes, which have not been investigated so far. With the help of these numbers, we look at the set of twin primes from a different perspective and bring the reader's attention to some characteristics potentially useful in tackling the Twin Prime Conjecture. To this purpose, we simplify the problem by dividing the positive integers into two complementary sets: one whose members lead to a pair of twin primes by a simple algebraic operation but cannot be directly calculated, and another one whose members do not lead directly to twin primes but are responsible for their distribution and can be directly calculated. By analyzing the facts from the perspective of the numbers in the second set, we reveal some interesting patterns and properties that suggest new approaches to the problem.

This work was conducted to characterize the 16S rRNA gene profile of a cohort of patients with traditional risk factors for developing atherosclerosis. The patients in the cohort were divided into two extremes; those predicted to develop extreme atherosclerosis who did not (Protected), and those predicted not to develop atherosclerosis who did (Unexplained). Bacterial DNA was isolated from stool and saliva and this was used to determine the V4 variable region of the 16S rRNA gene sequence composition of the samples in triplicate.