Tag: nevin manimala

Chaos. 2023 Mar;33(3):033120. doi: 10.1063/5.0134285.

ABSTRACT

Synchronization and resonance on networks are some of the most remarkable collective dynamical phenomena. The network topology, or the nature and distribution of the connections within an ensemble of coupled oscillators, plays a crucial role in shaping the local and global evolution of the two phenomena. This article further explores this relationship within a compact mathematical framework and provides new contributions on certain pivotal issues, including a closed bound for the average synchronization time in arbitrary topologies; new evidences of the effect of the coupling strength on this time; exact closed expressions for the resonance frequencies in terms of the eigenvalues of the Laplacian matrix; a measure of the effectiveness of an influencer node’s impact on the network; and, finally, a discussion on the existence of a resonant synchronized state. Some properties of the solution of the linear swing equation are also discussed within the same setting. Numerical experiments conducted on two distinct real networks-a social network and a power grid-illustrate the significance of these results and shed light on intriguing aspects of how these processes can be interpreted within networks of this kind.

PMID:37003810 | DOI:10.1063/5.0134285

Chaos. 2023 Mar;33(3):033143. doi: 10.1063/5.0135232.

ABSTRACT

This paper reports the novel results on fractional order-induced bifurcation of a tri-neuron fractional-order neural network (FONN) with delays and instantaneous self-connections by the intersection of implicit function curves to solve the bifurcation critical point. Firstly, it considers the distribution of the root of the characteristic equation in depth. Subsequently, it views fractional order as the bifurcation parameter and establishes the transversal condition and stability interval. The main novelties of this paper are to systematically analyze the order as a bifurcation parameter and concretely establish the order critical value through an implicit function array, which is a novel idea to solve the critical value. The derived results exhibit that once the value of the fractional order is greater than the bifurcation critical value, the stability of the system will be smashed and Hopf bifurcation will emerge. Ultimately, the validity of the developed key fruits is elucidated via two numerical experiments.

PMID:37003808 | DOI:10.1063/5.0135232

J Hazard Mater. 2023 Mar 28;452:131317. doi: 10.1016/j.jhazmat.2023.131317. Online ahead of print.

ABSTRACT

The primary environmental concern related to nuclear power is the production of radioactive waste hazardous to humans and the environment. The main scientific and technological problems to address this are related to the storage and disposal of the nuclear waste and monitoring the dispersion of radioactive species into the environment. In this work, we determined an anomalously high ¹⁴C activity, well above the modern natural background, on surface and seasonal snow sampled in early May 2019 on glaciers in the Hornsund fjord area (Svalbard). Due to the lack of local sources, the high snow concentrations of ¹⁴C suggest long-range atmospheric transport of nuclear waste particles from lower latitudes, where nuclear power plants and treatment stations are located. The analysis of the synoptic and local meteorological data allowed us to associate the long-range transport of this anomalous ¹⁴C concentration to an intrusion event of a warm and humid air mass that likely brought pollutants from Central Europe to the Arctic in late April 2019. Elemental and organic carbon, trace element concentration data, and scanning electron microscopy morphological analysis were performed on the same snow samples to better constrain the transport process that might have led to the high ¹⁴C radionuclide concentrations in Svalbard. In particular, the highest ¹⁴C values found in the snowpack (> 200 percent of Modern Carbon, pMC) were associated with the lowest OC/EC ratios (< 4), an indication of an anthropogenic industrial source, and with the presence of spherical particles rich in iron, zirconium, and titanium which, altogether, suggest an origin related to nuclear waste reprocessing plants. This study highlights the role of long-range transport in exposing Arctic environments to human pollution. Given that the frequency and intensity of these atmospheric warming events are predicted to increase due to ongoing climate change, improving our knowledge of their possible impact to Arctic pollution is becoming urgent.

PMID:37003004 | DOI:10.1016/j.jhazmat.2023.131317

EBioMedicine. 2023 Mar 30;90:104543. doi: 10.1016/j.ebiom.2023.104543. Online ahead of print.

ABSTRACT

BACKGROUND: Some observational studies found that dyslipidaemia is a risk factor for non-alcoholic fatty liver disease (NAFLD), and lipid-lowering drugs may lower NAFLD risk. However, it remains unclear whether dyslipidaemia is causative for NAFLD. This Mendelian randomisation (MR) study aimed to explore the causal role of lipid traits in NAFLD and evaluate the potential effect of lipid-lowering drug targets on NAFLD.

METHODS: Genetic variants associated with lipid traits and variants of genes encoding lipid-lowering drug targets were extracted from the Global Lipids Genetics Consortium genome-wide association study (GWAS). Summary statistics for NAFLD were obtained from two independent GWAS datasets. Lipid-lowering drug targets that reached significance were further tested using expression quantitative trait loci data in relevant tissues. Colocalisation and mediation analyses were performed to validate the robustness of the results and explore potential mediators.

FINDINGS: No significant effect of lipid traits and eight lipid-lowering drug targets on NAFLD risk was found. Genetic mimicry of lipoprotein lipase (LPL) enhancement was associated with lower NAFLD risks in two independent datasets (OR₁ = 0.60 [95% CI 0.50-0.72], p₁ = 2.07 × 10^-8; OR₂ = 0.57 [95% CI 0.39-0.82], p₂ = 3.00 × 10^-3). A significant MR association (OR = 0.71 [95% CI, 0.58-0.87], p = 1.20 × 10^-3) and strong colocalisation association (PP.H₄ = 0.85) with NAFLD were observed for LPL expression in subcutaneous adipose tissue. Fasting insulin and type 2 diabetes mediated 7.40% and 9.15%, respectively, of the total effect of LPL on NAFLD risk.

INTERPRETATION: Our findings do not support dyslipidaemia as a causal factor for NAFLD. Among nine lipid-lowering drug targets, LPL is a promising candidate drug target in NAFLD. The mechanism of action of LPL in NAFLD may be independent of its lipid-lowering effects.

FUNDING: Capital’s Funds for Health Improvement and Research (2022-4-4037). CAMS Innovation Fund for Medical Sciences (CIFMS, grant number: 2021-I2M-C&T-A-010).

PMID:37002989 | DOI:10.1016/j.ebiom.2023.104543

Clin Neurophysiol. 2023 Mar 21;150:49-55. doi: 10.1016/j.clinph.2023.02.180. Online ahead of print.

ABSTRACT

OBJECTIVE: We evaluated whether interictal epileptiform discharge (IED) rate and morphological characteristics predict seizure risk.

METHODS: We evaluated 10 features from automatically detectable IEDs in a stereotyped population with self-limited epilepsy with centrotemporal spikes (SeLECTS). We tested whether the average value or the most extreme values from each feature predicted future seizure risk in cross-sectional and longitudinal models.

RESULTS: 10,748 individual centrotemporal IEDs were analyzed from 59 subjects at 81 timepoints. In cross-sectional models, increases in average spike height, spike duration, slow wave rising slope, slow wave falling slope, and the most extreme values of slow wave rising slope each improved prediction of an increased risk of a future seizure compared to a model with age alone (p < 0.05, each). In longitudinal model, spike rising height improved prediction of future seizure risk compared to a model with age alone (p = 0.04) CONCLUSIONS: Spike height improves prediction of future seizure risk in SeLECTS. Several other morphological features may also improve prediction and should be explored in larger studies.

SIGNIFICANCE: Discovery of a relationship between novel IED features and seizure risk may improve clinical prognostication, visual and automated IED detection strategies, and provide insights into the underlying neuronal mechanisms that contribute to IED pathology.

PMID:37002980 | DOI:10.1016/j.clinph.2023.02.180

JMIR Med Educ. 2023 Mar 31. doi: 10.2196/44989. Online ahead of print.

ABSTRACT

BACKGROUND: A successful periodontitis treatment demands good manual skills. A correlation between biological sex and dental students’ manual dexterity is currently unknown.

OBJECTIVE: This study examines performance differences between male and female students within subgingival debridement.

METHODS: A total of 75 third-year dental students was divided by biological sex (male/female) and randomly assigned to one of two work methods (manual curettes, n=38; power-driven instruments, n=37). Students were trained on periodontitis models for 25 min daily over 10 days using the assigned manual or power-driven instrument. Practical training included subgingival debridement of all tooth types on phantom heads. Practical exams were performed after the training session (T1) and after 6 month (T2) and comprised subgingival debridement of four teeth within 20 min. The percentage of debrided root surface was assessed and statistically analyzed using a linear mixed-effects regression model (P<.05).

RESULTS: The analysis is based on 68 students (both groups n=34). The percentage of cleaned surfaces was not significantly different (P=.397) between male (mean 81.6, SD 18.2) and female (mean 76.3, SD 21.1) students, irrespective of the instrument employed. The use of power-driven instruments (mean 81.3, SD 20.5) led to significantly better results than the use of manual curettes (mean 75.4, SD 19.4; P=.023) and the overall performance decreased over time (T1: mean 84.5, SD 17.5; T2: mean 72.3, SD 20.8; P<.001).

CONCLUSIONS: Female and male students perform equally well in subgingival debridement. Therefore, sex-differentiated teaching methods are not necessary.

PMID:37002956 | DOI:10.2196/44989

Fam Pract. 2023 Apr 1:cmad035. doi: 10.1093/fampra/cmad035. Online ahead of print.

ABSTRACT

BACKGROUND: Little is known about the prevalence of frailty among patients with memory concerns attending a primary care-based memory clinic.

OBJECTIVE: This study aims to describe the prevalence of frailty among patients attending a primary care-based memory clinic and to determine if prevalence rates differ based on the screening tool that is used.

METHODS: We conducted a retrospective medical record review for all consecutive patients assessed in a primary care-based memory clinic over 8 months. Frailty was measured in 258 patients using the Fried frailty criteria, which relies on physical measures, and the Clinical Frailty Scale (CFS), which relies on functional status. Weighted kappa statistics were calculated to compare the Fried frailty and the CFS.

RESULTS: The prevalence of frailty was 16% by Fried criteria and 48% by the CFS. Agreement between Fried frailty and CFS was fair for CFS 5+ (kappa = 0.22; 95% confidence interval: 0.13, 0.32) and moderate for CFS 6+ (kappa = 0.47; 0.34, 0.61). Dual-trait measures of hand grip strength with gait speed were found to be a valid proxy for Fried frailty phenotype.

CONCLUSIONS: Among primary care patients with memory concerns, frailty prevalence rates differed based on the measure used. Screening for frailty in this population using measures relying on physical performance may be a more efficient approach for persons already at risk of further health instability from cognitive impairment. Our findings demonstrate how measure selection should be based on the objectives and context in which frailty screening occurs.

PMID:37002941 | DOI:10.1093/fampra/cmad035

Ophthalmic Physiol Opt. 2023 Apr 1. doi: 10.1111/opo.13136. Online ahead of print.

ABSTRACT

PURPOSE: The ±2.00 D accommodative facility test presents several limitations, including the lack of objective information and inherent characteristics such as vergence/accommodative conflict, change in apparent size of the image, subjective criteria for judging blur and motor reaction time. By using free-space viewing conditions and an open-field autorefractor to monitor the refractive state, we examined the impact of manipulating these factors on the qualitative and quantitative assessment of accommodative facility.

METHODS: Twenty-five healthy young adults (24.5 ± 4.5 years) took part in this study. Participants performed three accommodative facility tests (adapted flipper, 4D free-space viewing and 2.5D free-space viewing) under both monocular and binocular conditions in random order. A binocular open-field autorefractor was used to assess the accommodative response continuously, and these data were used to characterise accommodative facility quantitatively and qualitatively.

RESULTS: There were statistically significant differences between the three testing methods both quantitatively (p < 0.001) and qualitatively (p = 0.02). For the same accommodative demand, a lower number of cycles was obtained for the adapted flipper condition in comparison with the 4D free-space viewing test (corrected p-value < 0.001, Cohen’s d = 0.78). However, this comparison did not reach statistical significance for qualitative measures of accommodative facility (corrected p-value = 0.82, Cohen’s d 0.05).

CONCLUSIONS: These data provide evidence that the qualitative assessment of accommodative facility is not influenced by the inherent limitations of the ±2.00 D flipper test. The use of qualitative outcomes by incorporating an open-field autorefractor allows examiners to increase the validity of the accommodative facility test in both clinical and research settings.

PMID:37002939 | DOI:10.1111/opo.13136

Expert Rev Hematol. 2023 Apr 1. doi: 10.1080/17474086.2023.2199151. Online ahead of print.

ABSTRACT

INTRODUCTION: Interferons (IFNs) have been used for decades to treat polycythemia vera (PV). Single-arm clinical trials assessing IFN in PV patients demonstrated high hematological and molecular response rates, indicating potential disease-modifying activity of IFN. However, discontinuation rates of IFNs have been rather high due to frequent treatment-related side-effects.

AREAS COVERED: Ropeginterferon alfa-2b (ROPEG) is a monopegylated IFN consisting of a single isoform, which differentiates it from previous IFNs with respect to tolerability and dosing frequency. ROPEG has improved pharmacokinetic and pharmacodynamic properties, which allow extended dosing every two weeks and monthly administration during maintenance phase. This review covers ROPEG’s pharmacokinetic and pharmacodynamic properties, presents results of randomized clinical trials (RCT) that evaluated ROPEG in the treatment of PV patients, and discusses contemporary findings regarding the potential disease-modifying activity of ROPEG.

EXPERT OPINION: RCT have demonstrated high rates of hematological and molecular responses in PV patients treated with ROPEG, irrespective of thrombotic risk. Drug discontinuation rates were generally low. However, even though RCT captured the most important surrogate endpoints of thrombotic risk and disease progression in PV, they were not statistically powered to fully determine whether therapeutic intervention with ROPEG indeed has a direct positive effect on these important clinical outcomes.

PMID:37002907 | DOI:10.1080/17474086.2023.2199151

J Neurotrauma. 2023 Apr 1. doi: 10.1089/neu.2022.0339. Online ahead of print.

ABSTRACT

In the last decade, computational models of the brain have become the gold standard tool for investigating traumatic brain injury (TBI) mechanisms and developing novel protective equipment and other safety countermeasures. However, most studies utilizing finite element (FE) models of the brain have been conducted using models developed to represent the average neuroanatomy of a target demographic, such as the 50th percentile male. While this is an efficient strategy, it neglects normal anatomical variations present within the population and their contributions on the brain’s deformation response. As a result, the contributions of structural characteristics of the brain, such as brain volume, on brain deformation are not well understood. The objective of this study was to develop a set of statistical regression models relating measures of the size and shape of the brain to the resulting brain deformation. This was performed using a database of 125 subject-specific models, simulated under six independent head kinematic boundary conditions, spanning a range of impact modes (frontal, oblique, side), severity (non-injurious and injurious), and environments (volunteer, automotive, and American football). Two statistical regression techniques were utilized. Simple linear regression models were trained to relate intracranial volume (ICV) and the 95th percentile maximum principal strain (MPS-95) for each of the impact cases. Secondly, a partial least squares regression model was constructed to predict MPS-95 based on the affine transformation parameters from each subject, representing the size and shape of their brain, considering the six impact conditions collectively. Both techniques indicated a strong linear relationship between ICV and MPS-95, with MPS-95 varying by approximately 5% between the smallest and largest brains. This difference represented up to 40% of the mean strain across all subjects. This study represents a comprehensive assessment of the relationships between brain anatomy and deformation, which is crucial for the development of personalized protective equipment, identifying individuals at higher risk of injury, and using computational models to aid clinical diagnostics of TBI.

PMID:37002891 | DOI:10.1089/neu.2022.0339