This paper presents the results of investigating the dynamics of an economic system with chaotic behavior and a suboptimal control proposal to suppress the chaotic behavior. Numerical results using ...phase portraits, bifurcation diagrams, Lyapunov exponents, and 0-1 testing confirmed chaotic and hyperchaotic behavior. The results also proved the effectiveness of the control, showing errors below 1%, even in cases where the control design is subject to parametric errors. Additionally, an investigation of the system in fractional order is included, demonstrating that the system has periodic, constant, or chaotic behavior for specific values of the order of the derivative.
This paper investigates, through numerical simulations, the application of piezoelectric materials in energy generation. The mathematical model describes a U-shaped portal frame system, excited by an ...engine with unbalanced mass and coupled to a nonlinear energy sink (NES), which is used as a passive vibration absorber. The influence of the piezoelectric material parameters used in the energy collection and the dimensioning parameters of the NES system is deeply analyzed in this paper. Numerical simulations are presented considering all combinations of the parameters of the piezoelectric material model and the NES. The system dynamics were analyzed through phase diagrams and the 0–1 test. The estimation of energy collection was carried out by calculating the average power. The numerical results show that a more significant potential for energy generation is obtained for certain combinations of parameters, as well as chaotic behavior in some cases.
The present work presents the investigation of the dynamics and influence of chaotic behavior on energy capture for a U-shaped structure (portal frame) that contains shape memory alloy (SMA), ...piezoelectric material (PZT), a nonlinear energy sink (NES) and a non-ideal excitation source represented by an unbalanced electric motor coupled to the U-structure. The mathematical model presents nonlinearities arising from the nonlinear stiffness of the U-structure, the NES system, the SMA, and the PZT material. Chaotic behavior is assessed through time history, bifurcation diagrams, phase diagrams, and the 0–1 test. Energy capture is carried out through a piezoelectric material (PZT), represented by a non-linear electromechanical coupling model, and electromagnetic induction generated by the non-linear electromagnetic energy sink coupled to the structure (NES). Dynamic analysis is performed through parametric analysis of parameters related to piezoelectric coupling and NES parameters. Numerical simulations demonstrate that the system has chaotic behavior for specific parameters and that its energy capture is influenced by parametric variation. It is shown numerically that the parameters of the SMA material, the PZT material, and the NES significantly influence the chaotic behavior and energy capture of the investigated electromechanical system.
In recent years, the number of motor vehicles in circulation has increased in proportion to Brazil’s economic growth, resulting in an increase in emissions of toxic gases from combustion, such as ...nitrogen oxide, particulate matter, carbon dioxide and volatile organic compounds, among other polluting compounds. This type of pollution has its impacts potentiated in large cities, accumulating due to the configuration of streets and buildings in large urban centers, and can even penetrate indoor environments, having harmful effects on the health of residents. To minimize the emission of these gases, catalytic converters can be used in the vehicle exhausts. Catalytic converters are a promising technology used to reduce exhaust emissions from the engine. In this context, this paper presents an overview of the emission of toxic gases by heavy transport powered by diesel oil and the influence of the use of automotive catalysts in reducing the emission of toxic gases. Additionally, a proposal for monitoring the useful life of automotive catalysts is presented through an electronic sensing system, which makes it possible to determine the catalyst efficiency and the appropriate point for its reactivation or replacement.
In this work, an autocatalytic chemical reactions model with mutation is investigated, and a nonlinear control is proposed to lead the system to a behavior that maintains the system with a desired ...behavior and with suppress the chaotic behavior. Numerical results considering a broad analysis of the system parameters confirmed the chaotic behavior using phase portraits, bifurcation diagrams and Lyapunov exponents. An analysis of the system behavior in fractional order considering the Atangana–Baleanu–Caputo operator was performed to include the memory effect in the system dynamics. The numerical results obtained demonstrated that the system is extremely sensitive to variations in the order of the derivative, taking the system from chaotic behavior to periodic behavior with small variations in the order of the derivative. The chaotic behavior of the system is proven in fractional order by the 0–1 test and a scale index based on the wavelets test. The proposed control demonstrated to be efficient in maintaining the main product (ethanol) output concentration at the desired level.
•Observation of chaotic behavior in bioreactors•Influence of fractional order on the dynamics of nonlinear systems•Application of control in the optimization of biological processes
Natural killer (NK) cells comprise a heterogeneous population of cells important for pathogen defense and cancer surveillance. However, the functional significance of this diversity is not fully ...understood. Here, we demonstrate through transcriptional profiling and functional studies that the activating receptor DNAM-1 (CD226) identifies two distinct NK cell functional subsets: DNAM-1+ and DNAM-1− NK cells. DNAM-1+ NK cells produce high levels of inflammatory cytokines, have enhanced interleukin 15 signaling, and proliferate vigorously. By contrast, DNAM-1− NK cells that differentiate from DNAM-1+ NK cells have greater expression of NK-cell-receptor-related genes and are higher producers of MIP1 chemokines. Collectively, our data reveal the existence of a functional program of NK cell maturation marked by DNAM-1 expression.
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•The activating receptor DNAM-1 identifies two distinct NK cell functional subsets•DNAM-1+ NKs have enhanced IL-15 signaling and are a higher producer of cytokines•DNAM-1− NKs are higher producers of MIP1 chemokines•DNAM-1+ NKs differentiate into DNAM-1− NKs through an alternative maturation pathway
Martinet et al. demonstrate that DNAM-1-activating receptor expression identifies two distinct subsets of natural killer (NK) cells. DNAM-1+ NK cells proliferate vigorously, produce high levels of cytokines, and represent critical inflammatory and anti-tumor cells. By contrast, DNAM-1− NK cells that differentiate from DNAM-1+ NK cells are higher producers of MIP1 chemokines.
Previously, we discovered that ZFP57 is a maternal-zygotic effect gene, and it maintains DNA methylation genomic imprint at multiple imprinted regions in mouse embryos. Despite these findings, it ...remains elusive how DNA methyltransferases are targeted to the imprinting control regions to initiate and maintain DNA methylation imprint. To gain insights into these essential processes in genomic imprinting, we examined how ZFP57 maintains genomic DNA methylation imprint in mouse embryonic stem (ES) cells. Here we demonstrate that the loss of ZFP57 in mouse ES cells led to a complete loss of genomic DNA methylation imprint at multiple imprinted regions, similar to its role in mouse embryos. However, reintroduction of ZFP57 into Zfp57-null ES cells did not result in reacquisition of DNA methylation imprint, suggesting that the memory for genomic imprinting had been lost or altered in Zfp57-null ES cells in culture. Interestingly, ZFP57 and DNA methyltransferases could form complexes in the presence of KAP1/TRIM28/TIF1β when co-expressed in COS cells. We also found that the wild-type exogenous ZFP57 but not the mutant ZFP57 lacking the KRAB box that interacts with its co-factor KAP1/TRIM28/TIF1β could substitute for the endogenous ZFP57 in maintaining the DNA methylation imprint in ES cells. These results suggest that ZFP57 may recruit DNA methyltransferases to its target regions to maintain DNA methylation imprint, and this interaction is likely facilitated by KAP1/TRIM28/TIF1β.
Background: ZFP57 is a maternal-zygotic effect gene that maintains genomic imprinting in mouse embryos.
Results: KAP1 facilitates the interaction between ZFP57 and DNA methyltransferases. The KRAB box of ZFP57 is required for maintaining DNA methylation imprint in ES cells.
Conclusion: ZFP57 recruits DNA methyltransferases and maintains DNA methylation imprint through KRAB box-mediated interaction.
Significance: This work implies that ZFP57 recruits DNA methyltransferases via KAP1 to maintain DNA methylation imprint.
The electronic MEdical Records and GEnomics (eMERGE) network brings together DNA biobanks linked to electronic health records (EHRs) from multiple institutions. Approximately 51,000 DNA samples from ...distinct individuals have been genotyped using genome-wide SNP arrays across the nine sites of the network. The eMERGE Coordinating Center and the Genomics Workgroup developed a pipeline to impute and merge genomic data across the different SNP arrays to maximize sample size and power to detect associations with a variety of clinical endpoints. The 1000 Genomes cosmopolitan reference panel was used for imputation. Imputation results were evaluated using the following metrics: accuracy of imputation, allelic R (2) (estimated correlation between the imputed and true genotypes), and the relationship between allelic R (2) and minor allele frequency. Computation time and memory resources required by two different software packages (BEAGLE and IMPUTE2) were also evaluated. A number of challenges were encountered due to the complexity of using two different imputation software packages, multiple ancestral populations, and many different genotyping platforms. We present lessons learned and describe the pipeline implemented here to impute and merge genomic data sets. The eMERGE imputed dataset will serve as a valuable resource for discovery, leveraging the clinical data that can be mined from the EHR.
Community-based organizations (CBOs) deliver services in culturally-responsive ways, and could effectively partner with health centers to deliver HIV pre-exposure prophylaxis (PrEP) to Latino men who ...have sex with men (LMSM). However, few such models exist. We conducted a planning study in collaboration with three CBOs serving LMSM to identify optimal PrEP delivery strategies for health centers and CBOs to implement jointly. We established a Community Expert Panel (CEP) of eight client-facing CBO and health center staff. Over 6 months, the panel met monthly to identify collaborative strategies for PrEP delivery, using a modified Delphi method consisting of the following steps: (1) brainstorming strategies; (2) rating strategies on acceptability, appropriateness and feasibility; (3) review of data from qualitative focus group discussions with CBO clients; and (4) final strategy selection. The panel initially identified 25 potential strategies spread across three categories: improving communication between health centers and CBOs; using low-barrier PrEP options (e.g. telemedicine), and developing locally-relevant, culturally-sensitive outreach materials. Focus groups with CBO clients highlighted a desire for flexible options for PrEP-related care and emphasized trust in CBOs. The final package of strategies consisted of: (1) a web-based referral tool; (2) telemedicine appointments; (3) geographically-convenient options for lab specimen collection; (4) tailored print and social media; and (5) regular coaching sessions with CBO staff. Through a community-engaged process, we identified a package of PrEP delivery strategies that CBOs and health centers can implement in partnership, which have the potential to overcome barriers to PrEP for LMSM.
IMPORTANCE: Although parental leave is essential in enhancing resident wellness and fostering inclusive workplace environments, residents may often feel discouraged from using parental leave owing to ...perceived stigma and concerns about possible negative effects on their training. OBJECTIVE: To examine parental leave usage across multiple institutions and compare residency performance metrics between residents who took parental leave vs their peers who did not take leave. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective cross-sectional analysis conducted from April 1, 2020, to July 28, 2022, of educational records. Multicenter data were obtained from 10 Accreditation Council for Graduate Medical Education (ACGME)–accredited ophthalmology programs across the US. Included ophthalmology residents graduated between 2015 and 2019. Data were analyzed from August 15, 2021, to July 25, 2022. EXPOSURES: Performance metrics of residents who used parental leave during residency were compared with those of residents who did not take parental leave. MAIN OUTCOMES AND MEASURES: Measures of performance included the Ophthalmic Knowledge Assessment Program (OKAP) scores, ACGME milestones scores, board examination pass rates, research activity, and surgical volumes. RESULTS: Of the 283 ophthalmology residents (149 male 52.7%) included in the study, 44 (15.5%) took a median (IQR) parental leave of 4.5 (2-6) weeks. There were no differences in average OKAP percentiles, research activity, average ACGME milestones scores, or surgical volume between residents who took parental leave and those who did not. Residents who pursued fellowship were less likely to have taken parental leave (odds ratio OR, 0.43; 95% CI, 0.27-0.68; P < .001), and residents who practiced in private settings after residency were more likely to have taken parental leave (OR, 3.56; 95% CI, 1.79-7.08; P < .001). When stratified by sex, no differences were identified in performance between female residents who took parental leave compared with residents who did not take leave, except a mild surgical number difference in 1 subspecialty category of keratorefractive procedures (difference in median values, −2; 95% CI, −3.7 to −0.3; P = .03). CONCLUSIONS AND RELEVANCE: In this multicenter cross-sectional study, no differences in performance metrics were identified between residents taking parental leave compared with their peers. These findings may provide reassurance to trainees and program directors regarding the unlikelihood, on average, that taking adequate parental leave will affect performance metrics adversely.
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